750-184 CB_CBLE 125-200 HP (rev 1998)

$25.00 U.S.

Manual Part No. 750-184 8/98

CLEAVER-BROOKSMODEL CB, CB-LE

PACKAGED BOILER

125 through 200 HPFuel: Light Oil, Heavy Oil, Gas or Combination

Operation, Service, and Parts Manual

SAFETY PRECAUTIONS AND ABBREVIATIONS

Safety Precautions

It is essential to read and understand the following safetyprecautions before attempting to operate the equipment.Failure to follow these precautions may result in damage toequipment, serious personal injury, or death. A completeunderstanding of this manual is required before attempting tostart-up, operate or maintain the equipment. The equipmentshould be operated only by personnel who have a workingknowledge and understanding of the equipment.

The following symbols are used throughout this manual:

! DANGERWARNING

This symbol indicates a potentiallyhazardous situation which, i f notavoided, could resul t in ser iouspersonal injury, or death.

! DANGERCAUTION

This symbol indicates a potentially hazard-ous situation which, if not avoided, could re-sult in damage to the equipment.

Note: This symbol indicates informationthat is vital to the operation of thisequipment.

Abbreviations

Following is an explanation of the abbreviations, acronyms,and symbols used in this manual.

AC

Alternating CurrentAR Automatic Reset

ASME American Society of Mechanical EngineersASTM American Society of Testing and MaterialsBHP Boiler HorsepowerBTU British Thermal Unit

C Degrees CelsiusCFH Cubic Feet per HourCu Ft Cubic FeetDC Direct Current

F Degrees FahrenheitFM Factory MutualFS Flame Safeguardft Feet

GPM Gallons per MinuteHd HeadHT Height

HTB High Turndown BurnerHZ Hertz

In H

2

O Inches of WaterIRI Industrial Risk InsuranceLb Pound

LWCO Low-Water Cut-OffM Million

MFD Micro-Farad MR Manual Reset

NEC National Electric CodeNo. NumberpH Measure of the degree of acid or base of a

solutionP/N Part NumberPPM Parts Per MillionPR Program Relaypsi Pounds Per Square Inch

SAE Society of Automotive Engineersscfh Standard Cubic Feet per Hour

T TemperatureTC Temperature ControlTI Temperature Gauge

MODEL CB, CB-LEPACKAGED BOILER

Operation, Service, and Parts Manual

125 through 200 HPFuel: Light Oil, Heavy Oil Gas or Combination

Please direct purchase orders for replacement manuals to your local Cleaver-Brooks authorized representative

Manual Part No. 750-1848/98 Printed in U.S.A.

Cleaver-Brooks 1998

NOTE: If you have a CB-HAWK

Boiler Management ControlSystem, refer to CB-HAWK Installation, Operating and ServiceManual No. 750-133 during initial start up, and when referenc-ing Chapters 5, 6, and 7 in this manual.

i

TO:

Owners, Operators and/or Maintenance Personnel

This operating manual presents information that will help to properly operate and care for the equipment. Study its contents carefully. The unit will provide good service and continued operation if proper operating and maintenance instructions are fol-lowed. No attempt should be made to operate the unit until the principles of operation and all of the components are thoroughly understood. Failure to follow all applicable instructions and warnings may result in severe personal injury or death.It is the responsibility of the owner to train and advise not only his or her personnel, but the contractors' personnel who are ser-vicing, repairing or operating the equipment, in all safety aspects.

Cleaver-Brooks equipment is designed and engineered to give long life and excellent service on the job. The electrical and me-chanical devices supplied as part of the unit were chosen because of their known ability to perform; however, proper operating techniques and maintenance procedures must be followed at all times. Although these components afford a high degree of pro-tection and safety, operation of equipment is not to be considered free from all dangers and hazards inherent in handling and firing of fuel.

Any "automatic" features included in the design do not relieve the attendant of any responsibility. Such features merely free him of certain repetitive chores and give him more time to devote to the proper upkeep of equipment.

It is solely the operators responsibility to properly operate and maintain the equipment. No amount of written instructions can replace intelligent thinking and reasoning and this manual is not intended to relieve the operating personnel of the responsibility for proper operation. On the other hand, a thorough understanding of this manual is required before attempting to operate, main-tain, service, or repair this equipment.

Because of state, local, or other applicable codes, there are a variety of electric controls and safety devices which vary consid-erably from one boiler to another. This manual contains information designed to show how a basic burner operates.

Operating controls will normally function for long periods of time and we have found that some operators become lax in their daily or monthly testing, assuming that normal operation will continue indefinitely. Malfunctions of controls lead to uneconom-ical operation and damage and, in most cases, these conditions can be traced directly to carelessness and deficiencies in testing and maintenance.

It is recommended that a boiler room log or record be maintained. Recording of daily, weekly, monthly and yearly maintenance activities and recording of any unusual operation will serve as a valuable guide to any necessary investigation.

Most instances of major boiler damage are the result of operation with low water. We cannot emphasize too strongly the need for the operator to periodically check his low water controls and to follow good maintenance and testing practices. Cross-con-necting piping to low water devices must be internally inspected periodically to guard against any stoppages which could ob-struct the free flow of water to the low water devices. Float bowls of these controls must be inspected frequently to check for the presence of foreign substances that would impede float ball movement.

The waterside condition of the pressure vessel is of extreme importance. Waterside surfaces should be inspected frequently to check for the presence of any mud, sludge, scale or corrosion.

The services of a qualified water treating company or a water consultant to recommend the proper boiler water treating practices are essential.

The operation of this equipment by the owner and his or her operating personnel must comply with all requirements or regula-tions of his insurance company and/or other authority having jurisdiction. In the event of any conflict or inconsistency between such requirements and the warnings or instructions contained herein, please contact Cleaver-Brooks before proceeding.

DO NOT OPERATE, SERVICE, OR REPAIR THIS EQUIPMENT UNLESS YOU FULLY UNDERSTAND ALL APPLICABLE SECTIONS OF THIS MANUAL.

DO NOT ALLOW OTHERS TO OPERATE, SERVICE, OR REPAIR THIS EQUIPMENT UNLESS THEY FULLY UNDERSTAND ALL APPLICABLE SECTIONS OF THIS MANUAL.

FAILURE TO FOLLOW ALL APPLICABLE WARNINGS AND INSTRUCTIONS MAY RESULT IN SEVEREPERSONAL INJURY OR DEATH.

!

DANGERWARNING

TABLE OF CONTENTS

Chapter 1Basics of Firetube OperationA. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1B. The Boiler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2C. Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3D. Steam Controls (All Fuels) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5E. Hot Water Controls (All Fuels). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7F. Induced Flue Gas Recirculation Components (CB-LE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

Chapter 2Burner Operation and ControlA. The Burner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1B. Control And Component Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4C. Components Common To All Boilers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4D. Controls For Gas Firing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5E. Controls Common To Oil-Fired Boiler (Including Combination). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8F. Additional Controls For Heavy Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11G. Controls For Combination Burners Only. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12H. Combustion Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12I. Automatic Ignition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13J. Atomizing Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13K. Oil Fuel Flow - Light Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13L. Oil Fuel Flow - Heavy Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16M. Gas Fuel Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16N. Modulating Firing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16

Chapter 3Waterside Care And RequirementsA. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1B. Water Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1C. Water Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5D. Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5E. Boil-out Of A New Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6F. Washing Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7G. Blowdown Steam Boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7H. Periodic Inspection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9I. Preparation For Extended Lay-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9

ii

TABLE OF CONTENTS(continued)

Chapter 4Sequence Of OperationA. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1B. Circuit And Interlock Controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1C. Sequence Of Operation - Oil Or Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2D. Flame Loss Sequence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Chapter 5Starting And Operating InstructionsA. General Preparation for Start-up - All Fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1B. Control Settings-Steam and Hot Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2C. Gas Pilot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3D. Atomizing Air. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3E. Firing Preparations for No. 2 Oil (Series 100-200) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4F. Firing Preparations for No. 6 Oil (Series 400-600) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6G. Firing Preparations for Gas (Series 200-400-700). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7H. Induced Flue Gas Recirculation Set Up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8I. Start-up, Operating and Shutdown - All Fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10J. Control Operational Tests and Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11

Chapter 6Adjustment ProceduresA. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1B. Linkage - Modulating Motor & Air Damper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2C. Modulating Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3D. Modulating Motor Switches Low Fire and High Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3E. Burner Operating Controls General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4F. Modulating Pressure Controls (Steam) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6G. Operating Limit Pressure Control (Steam) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6H. High Limit Pressure Control - (Steam) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6I. Modulating Temperature Control - (Hot Water) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6J. Operating Limit Temperature Control - (Hot Water) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7K. High Limit Temperature Control - (Hot Water) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7L. Low-Water Cutoff Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7M. Combustion Air Proving Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7N. Atomizing Air Proving Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7O. Gas Pilot Flame Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8P. Gas Pressure and Flow Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9Q. Gas Fuel Combustion Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11R. Low-Gas Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13S. High-Gas Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14T. Fuel Oil Pressure and Temperature - General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14U. Fuel Oil Combustion Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17

iii

TABLE OF CONTENTS (continued)

Chapter 6 (continued)Adjustment ProceduresV. Burner Drawer Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18W. Oil Drawer Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18X. Low-Oil-Temperature Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18Y. High-Oil-Temperature Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18Z. Low-Oil-Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19AA. Electric Oil Heater Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19BB. Steam Oil Heater Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19CC. Hot Water Oil Heater Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19DD. Steam Heater Pressure Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19

Chapter 7Trouble Shooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

Chapter 8Inspection And MaintenanceA. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1B. Fireside Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2C. Water Level Controls and Waterside . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2D. Water Gauge Glass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3E. Electrical Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3F. Flame Safety Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4G. Oil Burner Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5H. Gas Burner Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7I. Motorized Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7J. Solenoid Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7K. Air Control Damper, Linkage and Cam Spring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7L. Forced Draft Fan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8M. CB-LE Fan/Motor Cassette Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9N. CB-LE Inspection and Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10O. CB-LE Airbox Gasket Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12P. CB-LE Fan/Motor Cassette Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12Q. Safety Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-19R. Fuel Oil Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-19S. Air Pump and Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-20T. Head Inspection and Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-23U. Refractory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-25V. Sealing and Closing Inner Door and Front Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-27W. Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-31X. Oil HeatersElectric, Steam, Hot Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-32Y. Combustion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-32Z. Air Pump Belt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-32

iv

Chapter 9Customer Service And Parts

Front Door, Inner Door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5Rear Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Dry Oven & Liner Tile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 8Impellers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9,10Jackshafts, Mod Motor, Air Damper Linkage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-15Burner Drawer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16, 17Burner Housing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18, 19Flame Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 21Entrance Box & Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22, 23Front Head Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24, 25Electric Oil Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26, 27Oil Emission Steam Electric Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28-30Air Compressor /Air Line Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-34Light Oil / Air Piping Front Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35, 36Gas Trains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37, 38Pressure Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39Temperature Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40, 41Water Column . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42, 43

Notesv

CHAPTER 1Basics of Firetube Operation

A. GENERAL

Firetube boilers are available for low or high pressure steam,or for hot water applications. Firetube boilers are typicallyused for applications ranging from 15 to 800 horsepower. Afiretube boiler is a cylindrical vessel, with horizontal tubespassing through and connected to the front and rear tubesheets. The vessel contains the water and absorbs the energy

steam or hot water. The primary purpose of the boiler is tosupply energy to the facilitys operations - for heat,manufacturing process, laundry, kitchen, etc. The nature ofthe facilitys operation will dictate whether a steam or hotwater boiler should be used.

Note: If your boiler is equipped with a CB-HAWK

boi ler management controlsystem, refer to CB-HAWK Installation,

A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1B. The Boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2C. Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3D. Steam Controls (All Fuels). . . . . . . . . . . . . . . . . . . 1-5E. Hot Water Controls (All Fuels) . . . . . . . . . . . . . . . . 1-7F. Induced Flue Gas Recirculation Components . . . . . 1-9generated from the flame. The front door and rear doorprovide the seal to contain the hot combustion gasses. Bafflesdesigned into the doors serve to redirect the combustiongasses through the various firetube passages. The flameoriginates in the furnace. As the combustion gasses traveldown the furnace and through the various firetube channels,heat from the flame and combustion gasses is transferred tothe water. Transferred energy develops into the required750-184

Figure: 1-1 FiretubOperating and Servicing Manual No. 750-133 for information regarding controlsdiscussed in Chapter 1.1-1

e Cut Away(Typical)

Chapter 1 Basics of Firetube Operation

thereby reducing NOx emissions. In this approach, thecombustion air fan handles both the combustion air and the

Rated Capacity 125 through 200hp

Operating Pressure Steam 15-250 psig, or higher if specified

Hot Water 30-250 psig or higher if specified

Fuel Oil or Gas or CombinationIgnition AutomaticFiring Full Modulation Through

Operating RangesBurner (Oil) (Low Pressure) Air AtomizingBurner (Gas) Non-premix Orificed TypeAir Damper Rotary Type

(Electrically Modulated)Steam Trim ASME CodeWater Trim ASME CodeThe LE Option, available on Cleaver-Brooks FiretubeBoilers, reduces Nitrogen Oxide (NOx) emissions, a majorprecursor to ozone pollution (smog). Carbon Monoxide (CO)emissions also tend to be lower, due to increased turbulencecaused by the addition of the flue gases into the combustionair stream, thereby improving combustion.

Note: For information on IFGR when firingheavy oi l , review the Operat ion andMaintenance manual for Heavy Oil Isolation750-171

The LE Option is used on Cleaver-Brooks Model CB Firetubeboilers firing either natural gas and/or light oil, and iscompatible with both hot water and steam systems.

The IFGR system mixes a portion of the relatively cool fluegas from the exit of the fourth-pass tubes with the incomingcombustion air to reduce the furnace flame temperature,The general information in this manual applies directly toCleaver-Brooks Model CB Boilers in sizes ranging from 125through 200 boiler horsepower for the following fuels:

Series 100 Light Oil (No. 2) Series 200 Light Oil (No. 2) Or GasSeries 400 Heavy Oil (No. 6) Or GasSeries 600 Heavy Oil (No. 6) OnlySeries 700 Gas Only

Note: Although the Series 400 or 600 burneris designed and designated to burn No. 6oil, the burner will handle grades 4 and 5equal ly wel l , w i th some possibleadjustments. While the manual containspertinent information on No. 6 fuel oil, allre ferences to No. 6 fue l should beconsidered applicable to all grades of heavyoil.1-2recirculated flue gases. Accordingly, this method is calledInduced Flue Gas Recirculation (IFGR), because the flue gasis induced into the fan inlet.

The LE Option, with its various levels of IFGR systems, canaffect the selection of the combustion air fan, motor, burner,and other components . Several d i fferent systemconfigurations are available, depending on the requirementsfor NOx emissions and the fuels used. All systems usesimilar primary components, but may have different linkagecontrols, IFGR damper, fan, and motor sizes.

Always order genuine Cleaver-Brooks parts from your localCleaver-Brooks authorized representative.

The boiler and related equipment installation are to be incompliance with the standards of the National Board of FireUnderwriters. Installation should also conform to state andlocal codes governing such equipment. Prior to installation,the proper authorities having jurisdiction are to be consulted,permits obtained, etc. All boilers in the above series comply,when equipped with optional equipment, to Industrial RiskInsurers (IRI), Factory Mutual (FM), or other insuringunderwriters requirements.

B. THE BOILERThe Model CB boiler is a packaged firetube boiler of weldedsteel construction and consists of a pressure vessel, burner,burner controls, forced draft fan, damper, air pump,refractory, and appropriate boiler trim.

The horsepower rating of the boiler is indicated by thenumbers following the fuel series. Thus, CB700-200indicates a gas-fired 200 hp boiler.

The firetube construction provides some characteristics that differentiate it from other boiler types. Because of its vessel size, the firetube contains a large amount of water, allowing it to respond to load changes with minimum variation in steam pressure.

Firetube boilers are rated in boiler horsepower (BHP), which should not be confused with other horsepower measure-ments.

Hot water is commonly used in heating applications with the boiler supplying water to the system at 180 F to 220 F. The operating pressure for hot water heating systems usually is 30 psig to 125 psig. 750-184

Basics of Firetube Operation Chapter 1

Steam boilers are designed for low pressure or high pressure applications. Low pressure boilers are limited to 15 psig design, and are typically used for heating applications. High pressure boilers are typically used for process loads and can have a design pressure of 75 to 350 psig.

Steam and hot water boilers are defined according to design pressure and operating pressure. Design pressure is the max-imum pressure used in the design of the boiler for the pur-pose of calculating the minimum permissible thickness or physical characteristics of the pressure vessel parts of the boiler. Typically, the safety valves are set at or below design pressure. Operating pressure is the pressure of the boiler at which it normally operates. The operating pressure usually is maintained at a suitable level below the setting of the pres-sure relieving valve(s) to prevent their frequent opening dur-ing normal operation.

The type of service that your boiler is required to provide hasan important bearing on the amount of waterside care it willrequire.

! DANGERCAUTION

Waterside care is of prime importance. For

Feedwater equipment should be checked and ready for use.Be sure that all valves, piping, boiler feed pumps, andreceivers are installed in accordance with prevailing codesand practices.

Water requirements for both steam and hot water boilers areessential to boiler life and length of service. Constantattention to water requirements will pay dividends in the formof longer life, less down-time, and prevention of costlyrepairs. Care taken in placing the pressure vessel into initialservice is vital. The waterside of new boilers and new orremodeled steam or hot water systems may contain oil, greaseor other foreign matter. A method of boiling out the vessel toremove accumulations is described in Chapter 3.

The operator should be familiar with Chapter 3 beforeattempting to place the unit into operation.

C. CONSTRUCTION

Steam boilers designed for 15 psig and hot water boilersdesigned for 250

F at 125 psi or less are constructed inaccordance with Section IV, Power Boilers, of ASME Code.

Steam boilers designed for operating pressures exceeding 15psig are constructed in accordance with Section 1, PowerBoilers, of the ASME Code. Hot water boilers designed foroperating temperatures above 250

F or 125 psi are likewisespecific information or assistance with yourwater treatment requirements, contact yourCleaver-Brooks service and parts represen-tative. Failure to follow these instructionscould result in equipment damage750-184built to ASME Code.1-3

Chapter 1 peration

1-4

CONTROL PAN

FORCED DRAFFAN MOTOR

FLAMEDETECT

ATOMIZING APRESSUR

GAUGE

MODULAMOTO

IGNITIOTRANSFOR

NOZZLEHOLDER

OIL BURNERPRESSURE

GAUGE

AUXILIALOW WA

ATOMIZIOIL TANK

MAIN GBasics of Firetube O750-184

Figure: 1-2 Typical Steam Boiler - Light Oil or Gas Fired (CB)

VENT VALVE

WATER COLUMN

WATER GLASSDRAIN VALVE

LOW WATER CUT-OFFAND PUMP CONTROL

OPERATING PRESSURE, HIGH LIMIT PRESSURE AND MODULATING PRESSURE CONTROLS

COMBUSTION AIRPROVIDING SWITCH

EL

ATOMIZING

PROVIDING

STEAM PRESSURE GAUGE

T

FUEL OILCONTROLLER

SWITCH

AIR

OR

IRE

FLEXIBLEOIL LINE

FLEXIBLEAIR LINE

TINGR

OIL SOLENOIDVALVES

NMER

OILSUPPLY LINE

OIL PIPINGTERMINAL BLOCK

OIL RETURN LINE

AIR PUMPMODULE

OIL STRAINER

RYTER CUTOFF

NG AIR

AS TRAIN

PILOT GAS TRAIN

MAIN GAS BUTTERFLY VALVE

STACK TEMPERTUREGAUGE

Basics of Firetube Operation pter 1

750-184

Figure: 1-3 Steam Controls

D. STEAM CONTROLS (ALL FUELS)

1. Operating Limit Pressure Control (Figure 1-3): Breaks acircuit to stop burner operation on a rise of boilerpressure at a selected setting. It is adjusted to stop or startthe burner at a preselected pressure setting.

2. High Limit Pressure Control (Figure 1-3): Breaks acircuit to stop burner operation on a rise of pressureabove a selected setting. It is adjusted to stop the burnerat a preselected pressure above the operating limitcontrol setting. The high limit pressure control isnormally equipped with a manual reset.

3. Modulating Pressure Control (Figure 1-3): Senses

1.

OPERATING

LIMIT

CONTROL

2.

HIGH

LIMIT

CONTROL

3.

MODULATING

CONTROL

1 2 3

Figure: 1-4 Low Water Cut Off (LWCO)changing boiler pressures and transmits the informationto the modulating motor to change the burner firing ratewhen the manual-automatic switch is set on automatic.

4. Low-Water Cutoff and Pump Control (Figure 1-4):Float-operated control responds to the water level in theboiler. It performs two distinct functions:

Stops firing of the burner if water level lowers below thesafe operating point. Energizes the low-water light in thecontrol panel; also causes low-water alarm bell (optionalequipment) to ring. Code requirements of some modelsrequire a manual reset type of low-water cutoff.

Starts and stops the feedwater pump (if used) to maintainwater at the proper operating level (Figure 1-5).

! DANGERCAUTIONDetermine that the main and auxiliary lowwater cutoffs and pump control are level af-ter installation and throughout the equip-ments operating life. Failure to follow theseinstructions could result in equipment dam-age.Cha1-5

Figure: 1-5 Low Water Cut Off Pump Control (Cutaway)


1-6

5. Water Column Assembly (Figure 1-6): Houses the low-water cutoff and pump control and includes the watergauge glass, gauge glass shutoff cocks.

keeping the float bowl clean and free of sediment. Asimilar drain valve is furnished with auxiliary low-watercutoff for the same purpose.

7. Water Gauge Glass Drain Valve (Figure 1-7): Provided toflush the gauge glass.

8. Vent Valve (Figure 1-7): Allows the boiler to be ventedduring filling, and facilitates routine boiler inspection asrequired by ASME Code.

9. Stack Temperature Gauge (Figure 1-7): Indicates flue gasoutlet temperature.

Figure: 1-7 LWCO and Gauge Glass

VENT

VALVE

DRAIN

VALVE

GAUGE GLASSDRAIN VALVE

10. Auxiliary Low-water Cutoff (Figure 1-8): Breaks thecircuit to stop burner operation in the event boiler waterdrops below the master low-water cutoff point. Manualreset type requires manual resetting in order to start theburner after a low-water condition.

Figure: 1-8 Auxiliary Low Water Cut OffFigure: 1-6 Water Column Assembly6. Water Column Drain Valve (Figure 1-6): Provided so thatthe water column and its piping can be flushed regularlyto assist in maintaining cross-connecting piping and inFLUE GAS OUTLET TEMP.GAUGE750-184


750-184

11. Safety Valve(s) (Figure 1-9): Prevent buildup over thedesign pressure of the pressure vessel. The size, ratingand number of valves on a boiler is determined by theASME Boiler Code. The safety valves and the discharge

Figure: 1-9 Safety Valves

Figure: 1-11 Water Temperature Gauge

DISCHARGE OPENING MUST BE EQUAL TO OR LARGER

TOUCH DRIP PAN EXTEN-SION

SUPPORT FROM BUILDINGCONSTRUCTION

DRIP PANAND ELBOW

DRIP PANDRAIN

OPEN DRAINTO WASTE

BOILER SHELL

SAFETY VALVE

DRAIN

WATER LEVEL

NOTICE: BACK-PRESSURE OF STEAM EXHAUST SYSTEM MUST BE LESS THAN 6% OF SAFETY VALVE SETTING.

Figure: 1-10 Recommended Piping For Steam Relief Valve (Not furnished by Cleaver-Brooks)

1 1/2

MIN

.piping are to be installed to conform to the ASME coderequirements. The installation of a valve is of primaryimportance to its service life. A valve must be mountedin a vertical position so that discharge piping and code-required drains can be properly piped to prevent buildupof back pressure and accumulation of foreign materialaround the valve seat area. Apply only a moderateamount of pipe compound to male threads and avoidovertightening, which can distort the seats. Use only flat-jawed wrenches on the flats provided. When installing aflange-connected valve, use a new gasket and draw themounting bolts down evenly. Do not install or removeside outlet valves by using a pipe or wrench in the outlet.

! DANGERWARNINGOnly properly certified personnel such asthe safety valve manufacturers certifiedrepresentative can adjust or repair theboiler safety valves. Failure to follow theseinstruct ions could result in seriouspersonal injury or death

E. HOT WATER CONTROLS (ALL FUELS)

1. Water Temperature Gauge (Figure 1-11): Indicates theboiler internal water temperature.

2. Operating Limit Temperature Control (Figure 1-12):Breaks a circuit to stop burner operation on a rise ofboiler temperature at a selected setting. It is adjusted tostop or start the burner at a preselected operatingtemperature.

3. High Limit Temperature Control (Figure 1-12): Breaks acircuit to stop burner operation on a rise of temperatureat a selected setting. It is adjusted to stop burner at apreselected temperature above the operating controlsetting. The high limit temperature control normally isequipped with a manual reset.

4. Modulating Temperature Control (Figure 1-12): Senseschanging boiler water temperature and transmits theinformation to the modulating motor to change theTHAN INLET

VENT PIPE MUST NOT

VENT

DRIP PANEXTENSION

VENT PIPETO STEAM1-7


1-8

set on automatic.

5. Low-Water Cutoff (Figure 1-13): Breaks the circuit tostop burner operation if the water level in the boiler dropsbelow safe operating point, activating low-water lightand optional alarm bell if burner is so equipped.

6. Auxiliary Low-Water Cutoff (Figure 1-14) (Optional):Breaks the circuit to stop burner operation if the waterlevel in the boiler drops below the master low-watercutoff point.

7. Safety Valve(s) (Figure 1-9): Relieves the boiler ofpressure higher than the design pressure or a lowerpressure, if designated. Relief valves and their dischargepiping are to be installed to conform to ASME Coderequirements.

! DANGERWARNING

Only properly certified personnel such asthe relief valve manufacturers certifiedrepresentative can adjust or repair theboiler relief valves. Failure to follow theseinstruct ions could result in serious

Figure: 1-13 Low Water Cutoff (LWCO Hot Water)

Figure: 1-14 Auxiliary Low-Water Cutoffpersonal injury or death.

Figure: 1-12 Hot Water Controlsburner firing rate when the manual-automatic switch is750-184


F. I

1. Flue Gas Transfer Port, IFGR Damper, and Flange Collar(Figure 1-15). The flue gas transfer port is a tube thatallows the flue gases to travel from the exit of the fourth-pass tubes to the entrance of the combustion air fan.

The IFGR damper controls the volume of flue gas inducedinto the combustion air stream. The damper is located inthe flue gas transfer port and is positioned by the controllinkage.

2. IFGR Damper Linkage (Figure 1-16). The IFGR damperis positioned by the control linkage. The linkage couldconsist of a single arm, or it could consist of several armsdriven from the jackshaft to provide modulating control(see Figure 1-16).

3. Over-Travel Mechanism (Figures 1-15 and 1-16). Theover-travel mechanism has two functions. It allows thelinkage to pass through the front door, and it allowsjackshaft rotation to exceed (over travel) IFGR linkage

tay in afixed position while the jackshaft rotates.

4. Fuel Change-Over Linkage (Figure 1-16). When a boileris equipped to fire either gas or oil (dual-fuel boilers), andthe required NOx levels are below 60 ppm on natural gas,a dual-linkage arrangement is used to provide the differentrecirculation rates required for each fuel. Two jackshaftdrive arms are provided, one for oil and one for gas. Thelinkage is manually connected to the appropriate arm,based on the fuel being used.

On dual-fuel boilers with two jackshaft drive arms, asdefined above, a proximity switch is used to prove that thecorrect linkage connection is made. (Refer to the wiringdiagram provided with the boiler.)

5. Fan/Motor Cassette. The fan and motor assemblies aredesigned as a cassette so that they can be removed from thefront of the boiler, without opening the front door. Thefront door davit arm can be used to remove the assembly.

COMBUSTION AIR INLET

FRONT DOOR

CASSETTE MOUNTING BOLTSAIRBOX GASKET

CASSETTE LIFTING EYES

FAN/MOTOR CASSETTE

FLUE OUTLET

AIRBOX

FLUE GAS TRANSFERPORT WITH IFGR DAMPER

FOURTH-PASS TUBES

DAMPER DRIVE ARM

BACKPLATE GASKETINSULATED PARTITIONFigure: 1-15 Induced Flue Gas Recircu

FLANGE COLLAR

COMBUSTION AIR FAN

OVER-TRAVEL MECHANISM

IFGR DAMPER LINKAGEQUICK DISCONNECT LINKAGE

JACKSHAFT ARM

BURNER DRAWER

BURNER DRAWER SUPPORTS

INNER PLATE CLAMPS

FRONT DOOR BOLTS

FLUE GAS FLOW

COMBUSTION AIR FLOW

WINDBOX

REAR BURNER DRAWER GASKET

INSULATION (20-30 PPM NOx SYSTEMS)750-184lation System, General Arrangement

THROAT AND LINER TILE

FURNACE

GAS SPUDS

BURNER HOUSINGFGR COMPONENTS (CB-LE) movement. A set of springs allows the linkage to s1-9


1-10

6. Burner Drawer (Figure 1-15). The gas spudding patternfor the IFGR system may be different than that of a non-IFGR CB Burner of the same horsepower (HP) modeldesignation.

7. Combustion Air Inlet (Figure 1-15). The combustion airinlets are located at the top of the front door. Air entersfrom the rear of the air inlet shrouds, which reduces the

sound level and captures heat from the boiler and stackflue outlet.

8. Front Door Insulation (Figure 1-15). If NO

x

emissionsare below 60 PPM, the front door is insulated inside tocontrol temperature build up. The insulation is held inplace with wire mesh.

IFGR DAMPER CONTROL

JACKSHAFT

GAS JACKSHAFT DRIVE ARM

DUAL FUEL ARRANGEMENT

60

*

OVER-TRAVEL MECHANISM

JACKSHAFT LINKAGE ROD

QUICK-DISCONNECT LINKAGEOIL JACKSHAFT DRIVE ARM

PROXIMITY SWITCH JACKSHAFT ARM

*

NOMINAL: ACTUAL POSITION VARIES NOx REQUIREMENTWITH

Figure: 1-16 IFGR Damper Linkage

AND 60 PPM SYSTEM

(Except 60 ppm)SINGLE FUEL ARRANGEMENT30*750-184

with the operating, limit and interlock devices. The devicesare wired into the circuitry to provide safe operation andprotect against incorrect operating techniques.

AIR

DAMPER

CLOSED

Figure: 2-1 Burner Drawerconditions, excess steam pressure, or water temperature.

Safety interlock controls include combustion and atomizingair proving switches and, depending upon the fuel andinsurance carrier requirements, controls that prove thepresence of adequate fuel pressure, plus temperature provingcontrols when heated fuel oil is used.

The sequence of burner operation from startup through

through a linkage system connected to the gas butterfly valveand/or oil through a cam-operated metering valve. Fuel inputand air are thus properly proportioned for most efficientcombustion.

Filtered primary air for atomizing fuel oil is furnishedindependently of combustion air by an air pump. Thestandard 60 firetube boiler is equipped with the belt drivenCHAPTBurner Operatio

A. THE BURNER The oil burner is of the low pressure, air atomizing (nozzle)type. The gas burner is of the non-premix orifice type. Theburners are ignited by spark ignited gas pilot. The pilot is ofthe interrupted type and is extinguished after main flame isestablished.

Note: A Series 100 boi ler is usual lyequipped with a light oil pilot, although agas pilot is also available.

Burners equipped to burn oil and gas (combination burners)include equipment for each distinct fuel. Since the burneruses only one type of fuel at a time, a gas/oil selector switchis incorporated.

Regardless of which fuel is used, the burner operates with fullmodulation (within its rated operating range). The burnerreturns to minimum firing position for ignition. High-pressure boilers (above 15 psi) can be wired for both low-pressure and high-pressure modulation, which enables theboiler to operate at lower pressure during off-load hours, but

A. The Burner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1B. Control And Component Function . . . . . . . . . . . . . 2-4C. Components Common To All Boilers . . . . . . . . . . . 2-4D. Controls For Gas Firing . . . . . . . . . . . . . . . . . . . . . 2-5E. Controls Common To Oil-fired Boiler (Including Combination) . . . . . . . . . . . . . . . . . . . . . 2-8F. Additional Controls For Heavy Oil . . . . . . . . . . . . 2-11750-184

shutdown is governed by the program relay in conjunctionER 2n and Control

AIR DAMPER OPEN

G. Controls For Combination Burners Only . . . . . . . 2-12H. Combustion Air . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12I. Automatic Ignition . . . . . . . . . . . . . . . . . . . . . . . . . 2-13J. Atomizing Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13K. Oil Fuel Flow - Light Oil . . . . . . . . . . . . . . . . . . . 2-13L. Oil Fuel Flow - Heavy Oil . . . . . . . . . . . . . . . . . . . 2-16M. Gas Fuel Flow. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16N. Modulating Firing . . . . . . . . . . . . . . . . . . . . . . . . . 2-16at a somewhat reduced steam output, dependent upon lowersteam pressure and steam nozzle sizing.

The flame safeguard and program relay include a flamedetector to supervise both oil and gas flames, and to shut theburner down in the event of loss of flame. The programmingportion of the control provides a pre-purging period, provingof the pilot and main flame, and a period of continued bloweroperation to postpurge the boiler of all unburned fuel vapor.Other safety controls shut down the burner under low-waterAll CB boilers have the burner assembly attached to the fronthead. The entire head may be swung open for inspection andmaintenance.

Combustion air is provided by a centrifugal blower located inthe front head (Figure 2-5, 2-7 & 2-8). Combustion air flowdiagrams for both the CB-LE and the standard CB boiler areshown in figure 2-2 and figure 2-3. Combustion air deliveryto the burner is under the control of the modulating motor(Figure 2-4). The motor also regulates the flow of fuel2-1

air pump (Figure 2-5). The 60 CB-LE uses the framemounted air pump (Figure 2-6).

Chapter 2

Air Inlet2-2

The burner control circuit operates on 115 volt, single phase60 Hz (or 50 Hz when equipped) alternating current. Theforced draft fan motor is generally operated on 3-phaseservice at the available main power supply voltage.

or

Figure: 2-2 Air Intake Through Front Head

Figure: 2-3 Secondary Air Flow (CB-LE)Burner Operation and Control

Figure: 2-4 Modulating MotFigure: 2-5 Belt Driven Figure: 2-6 Frame Mounted Air CB Option)Indicator lights signaling loand flame failure condition

In addition to the standardevices may be required toinsurance carrier or local c(WD) prepared by Cleainstallation to determine tand limit control circuicomponents is outlined sequence is covered in Cha

Figure: 2-8 Forced Draft Fanad demand, fuel valve, low water,Figure: 2-7 Forced Drafts

d mov

hetsinp Fan Motor CB-LEAir Pump (CB) Pump (CB-LE or 750-184

are standard equipment.

basic controls supplied, othereet specific requirements of an

de. Refer to the Wiring Diagramer-Brooks for your specific specific controls in the burner. The function of individual Chapter 2 and the electricalter 3.

Burner Operation and Control Chapter 2

750-184

Note : Th is figure sharrangement for a stand

1.

FORCED

DRAFT

FAN

MOTOR

(

FIGU

2.

FORCED

DRAFT

FAN

(

FIGURE

2-83.

MODULATING

MOTOR

(

FIGURE

2-44.

MODULATING

MOTOR

TRANSFORM

5.

FORCED

DRAFT

FAN

MOTOR

STAR

6.

IGNITION

TRANSFORMER

7.

LOW

FIRE

SWITCH

8.

ATOMIZING

AIR

PROVING

SWITCH

9.

MANUAL

-

AUTOMATIC

SWITCH

10.

MANUAL

FLAME

CONTROL

11.

BURNER

SWITCH

12.

FLAME

DETECTOR

5

11

13

3, 4, 7

910

152-3

1, 2

6

ows f ront doorard CB. RE 2-7 CB-LE)

))ERTER

Figure: 2-9 Controls Common to All Boilers

13. COMBUSTION AIR PROVING SWITCH14. ALARM15. STACK THERMOMETER16. DIFFUSER17. ROTARY AIR DAMPER18. PRESSURE GAUGE

12

8

14

18

16

17

Chapter 2 Burner Operation and Control

10. Manual Flame Control (Figure 2-9): A manuallyo g ofth henthe manual-automatic switch is set on manual. It isused primarily for initial or subsequent setting of fuelinput throughout the firing range. It has no control overthe firing rate when the manual-automatic switch is seton automatic.

11. Burner Switch (Figure 2-9 & 2-10): A manually operatedstart-stop switch for directly starting and stoppingoperation of burner.

12. Flame Detector (Figure 2-9): Monitors gas or oil pilotand energizes the programmer flame relay in response toa flame signal. It continues to monitor main flame (oil orgas) after expiration of pilot providing period. A standardequipped boiler has a lead sulfide (infrared sensitive)detector.

13. Combustion Air Proving Switch (Figure 2-9): Apressure-sensitive switch actuated by air pressure fromthe forced draft fan. Its contacts close to prove presence

B. CONTROL AND COMPONENT FUNCTION

The term control covers the more important valves andcomponents, including, but not limited to electrical controlsor those monitored by the program relay. The operator mustbecome familiar with the individual functioning of allcontrols before understanding boiler operation andprocedures outlined in this manual.

Before proceeding, identify and locate each item using thecallout in the illustration.

The actual controls furnished with any given boiler willdepend upon the type of fuel for which it is equipped, andwhether it is a hot water or steam boiler. Refer to theapplicable group or groups within Chapter 2 that apply to theparticular boiler.

Boilers with optional features may have controlcomponents not listed here.

C. COMPONENTS COMMON TO ALL BOILERS

1. Forced Draft Fan Motor (Figure 2-7): Drives the forceddraft fan directly to provide combustion air. Also referredto as a blower motor.

2. Forced Draft Fan (Figure 2-8): Provides all air, underpressure, for combustion of pilot fuel and main fuel, andfor purging.

3. Modulating Motor (Figure 2-4 & 2-9): Operates therotary air damper and fuel metering valves through a camand linkage system to provide proper air/fuel ratios underall boiler load conditions.

4. Modulating Motor Transformer (Figure 2-9) (located inthe mod motor): Reduces control circuit voltage (115Vac) to required voltage (24Vac) for operation of themodulating motor.

5. Forced Draft Fan Motor Starter (Figure 2-9 & 2-10):Energizes forced draft fan (blower) motor.

6. Ignition Transformer (Figure 2-9): Provides high voltagespark for ignition of gas pilot or light oil pilot.

7. Low Fire Switch (Not Shown, located in the mod motor):An internal auxiliary switch, cam actuated by the motorshaft, which must be closed to indicate that the airdamper and fuel metering valve are in the low fireposition before an ignition cycle can occur.

8. Atomizing Air Proving Switch (Figure 2-10): Apressure-sensitive switch actuated by air pressure fromthe Air Pump. Its contacts close to prove presence ofatomizing air. The fuel valves cannot be energized unlessthis switch is satisfied.2-49. Manual-Automatic Switch (Figure 2-9): When set atautomatic, subsequent operation is at the command ofthe modulating control, which governs the position of themodulating motor in accordance with load demand.When set at manual, the modulating motor, through themanual flame control, can be positioned at a desiredburner firing rate. The primary purpose of the manualposition is for testing and setting the air/fuel ratiothrough the entire firing range.

Figure: 2-10 Control Boxperated potentiometer that permits the positionine modulating motor to a desired burner firing rate w750-184

r 2

D. CONTROLS FOR GAS FIRING

Depending upon the requirements of the insurance carrier orother governing agencies, the gas flow control system, or gastrain, may consist of some, or all, of the following items.Refer to the Dimension Diagram (DD) prepared by Cleaver-Brooks for your specified installation.

1. Gas Pilot Valve (Figure 2-11): A solenoid valve thatopens during the ignition period to admit fuel to the pilot.It closes after main flame is established. The sequence ofenergizing and de-energizing is controlled by theprogramming relay. A second gas pilot valve may berequired by insurance regulations.

2. Gas Pilot Vent Valve (Figure 2-11): When a second gaspilot valve is required, a normally open vent valve(optional equipment) is installed between them. Itspurpose is to vent gas to the atmosphere, should any be

2

4

5

Burner Operation and Control

of combustion air. The fuel valves cannot be energizedunless this switch is satisfied. The combustion airproving switch is provided on al l gas fired orcombination gas-oil burners. An oil fired boiler does notnormally have a separate switch but utilizes theatomizing air proving switch to the same effect, since thepresence of atomizing air from the air pump, which isbelt driven from the blower motor, is evidence of bloweroperation.

14. Alarm (Figure 2-9): Sounds to notify the operator of acondition requiring attention. The alarm is available asoptional equipment.

15. Stack Thermometer (Figure 2-9): Indicates temperatureof vented flue gases.

16. Diffuser (Figures 2-9): A circular plate, located at thefurnace end of the burner drawer, that imparts a rotaryswirling motion to combustion air immediately prior toits entering the flame, thus providing a thorough andefficient mixture with the fuel.

17. Rotary Air Damper (Figures 2-9): Provides accuratecontrol of combustion air in proportion to fuel input forvarious load demands. It consists of two concentriccylinders with openings. The outer is stationary. Theinner is rotated, under control of the modulating motor,to vary the effective size of the openings where theyoverlap.

18. Indicator Lights (Figure 2-10): Provide visualinformation of boiler operation as follows (indicatorlights vary with controls provided):

Flame Failure

Load Demand

Fuel Valve (valve open)Low Water

19. Program Relay and Flame Safeguard Control (Figure 2-9): Automatically programs each starting, operating andshutdown period in conjunction with operating limit andinterlock devices. Includes, in a timed and propersequence, the operation of the blower motor, ignitionsystem, fuel valve(s), and the damper motor. Thesequence includes air purge periods prior to ignition andupon burner shutdown.

The flame detector portion of the control monitors both oiland gas flames and provides protection in the event of loss ofa flame signal.

The control recycles automatically during normal operation,or following a power interruption. It must be manually resetfollowing a safety shutdown caused by a loss of flame. Aninternal checking circuit, effective on every start, preventsburner operation in the event anything causes the flame relay750-184

to hold in during this period.1

3

1. GAS PILOT VALVES2. GAS PILOT VENT VALVE3. GAS PILOT SHUTOFF COCK4. GAS PRESSURE GAUGE5. GAS PRESSURE REGULATING VALVEChapte2-5

Figure: 2-11 Pilot Gas Train


Figure: 2-12 Burner Drawer Back Plate

Figure: 2-13 Gas Modulating Cam

open a circuit causing the main gas valve(s) to close, or prevent the burner from starting. The switch is usually equipped with a device that must be manually reset after being tripped.

15. Leakage Connection (Not Shown): The body of the gasvalve has a plugged opening that is used whenever it isnecessary to conduct a test for possible leakage across theclosed valve.present in the pilot line when the pilot valves are closed.The valve closes when the pilot valves are energized.

3. Gas Pilot Shutoff Cock (Figure 2-11): For manuallyopening or closing the gas supply to gas pilot valve.

4. Gas Pressure Gauge (Figure 2-11): Indicates gaspressure to pilot.

5. Gas Pressure Regulating Valve (Figure 2-11): Reducesincoming gas pressure to suit the pilot.

6. Gas Pilot Aspirator (Figure 2-12): Provides completemixing of gas and air to the pilot.

7. Gas Pilot Adjusting Cock (Figure2-12): Regulates thesize of the gas pilot flame.

8. Gas Modulating Cam (Figure 2-13): An assembly,consisting of a quadrant, a series of adjustable allen-headscrews and a contour spring, provided for adjustment ofgas input at any point in the modulating range.

9. Main Gas Cock (Figure 2-14, 15): For manually openingand closing the main fuel gas supply downstream of themain gas line pressure regulator. A second shutoff cock,downstream of the main gas valve(s), is installed toprovide a means of shutting off the gas line whenever atest is made for leakage across the main gas valve.

10. Butterfly Gas Valve (Figure 2-14, 15): The pivoted discin the valve is actuated by connecting linkage from thegas modulating cam to regulate the rate of gas flow to theburner.

11. Main Gas Valves (Figure 2-14, 15): Electrically actuatedshutoff valves that open simultaneously to admit gas tothe burner. The downstream valve is equipped with aproof of closure switch that is connected into the pre-ignition interlock circuit.

12. Main Gas Vent Valve (Figure 2-14, 15): A normally opensolenoid valve installed between the two main gas valvesto vent gas to the atmosphere should any be present in themain gas line when the gas valves are deenergized. Thevent valve closes when the gas valves are energized.

13. Low Gas Pressure Switch (Figure 2-14, 15): A pressure-actuated switch that is closed whenever main gas linepressure is above a preselected pressure. Should thepressure drop below the setting, the switch contacts opena circuit causing the main gas valve(s) to close, orprevent the burner from starting. The switch is usuallyequipped with a device that must be manually reset afterbeing tripped.

14. High Gas Pressure Switch (Not Shown): A pressure actuated switch that is closed whenever main gas line pressure is below a preselected pressure. Should the pressure rise above the setting, the switch contacts will 2-6766. GAS PILOT ASPIRATOR7. GAS PILOT ADJUSTING COCK750-184


750-184

10

9

11

13

GAS FLOW

PRESSUREREGULATING

VALVE (UTILITIES)

*FURNISHED BYCLEAVER-BROOKS

ON SPECIAL ORDER O

ROTARY AIRDAMPER

Figure: 2-14 Gas Train (CB-HAWK)

9.

MAIN

GAS

COCK

10.

BUTTERFLY

GAS

VALVE

11.

MAIN

GAS

VALVES

12.

MAIN

GAS

VENT

VALVE

13.

GAS

PRESSURE

SENSOR

9AIR FLOW SECONDARY AIRTO BURNERGAS TOBURNER122-7

*PRESSUREREGULATING VALVE

(CUSTOMERS)

NLY

METER (UTILITIES)MAIN GASSHUTOFF

COCKMAIN

GAS VALVE (S)BUTTERFLYGAS VALVE

GAS PILOTPRESSURE REGULATOR

GAS PILOTPRESSURE GAUGE

GAS PILOTVALVE

OIL BURNER NOZZLEDIFFUSER

GAS PILOT

GAS TOBURNER

GAS PILOTSHUTOFF COCK

GAS PILOTADJUSTING COCK

Figure: 2-15 Secondary Air Flow With Gas Train

Chapter 2 ation and Control

E. CONTFIRED

The following items are applicable to all oil fired or gas andoil fired boilers. Additional controls for No. 6 oil are listed inSection I.

1. Oil Drawer Switch (Figure 2-16): Opens the limit circuitif oil drawer burner gun is not latched in the forwardposition required for burning oil.

2. Atomizing Air Proving Switch (Figure 2-16): Pressure-actuated switch whose contacts are closed whensufficient atomizing air pressure from the air pump ispresent for oil firing. Oil valve(s) will not open, or willnot remain open, unless switch contacts are closed.

3. Atomizing Air Pressure Gauge (Figure 2-16): Indicatesthe atomizing air pressure at the burner gun

4. Oil Solenoid Valve (Figure 2-16): Opens when energizedthrough contacts in the programmer and allows fuel oilflow from the oil metering valve to the burner nozzle. Alight oil fired burner uses two valves operatingsimultaneously.

lydll

controllers have the following integral parts. In additionto these, the controller used on a No. 6 oil fired burner hasadditional components described in Section I.

A.Oil Metering Valve: Valve metering stem moves toincrease or decrease the orifice area to regulate thesupply of fuel oil to the burner nozzle in accordancewith boiler load variances. Stem movement iscontrolled by the modulating motor through linkageand the oil metering cam.

B. Oil Modulating Cam: Assembly consisting of aquadrant, a series of adjustable allen-head screws anda contour spring provided for adjustment of oil inputat any point in the modulating range.

C. Oil Burner Pressure Gauge: Indicates pressure of thefuel oil at the metering valve.

D.Oil Pressure Regulator: For adjustment of the pressureof oil at the metering valve.

6. Oil Relief Valve (Figure 2-16): Maintains a constant oilsupply pressure to the fuel oil controller by bypassingexcess fuel oil.

11. OIL DRAWER SWITCH2. ATOMIZING AIR PROVING SWITCH3. ATOMIZING AIR PRESSURE GAUGE4. OIL SOLENOID VALVE

5

3

4 22-8Figure: 2-16 Components C5. FUEL OIL CONTROLLER6. OIL RELIEF VALVE7. TERMINAL BLOCK

67Burner OperROLS COMMON TO OIL-BOILERS (INCLUDING COMBINATION)

5.omFuel Oil Controller (Figures 2-16 & 2-17): An assembcombining into a single unit the gauges, regulators anvalves required for regulating the flow of fuel oil. A750-184mon to Oil Fired Boilers


750-184

PACKING

OIL PRESSURE REGULATOR

OIL SUPPLY

OIL RETURN

TO MAIN OIL SOLENOID VALVE

Figure: 2-17 Oil Control Valve Assembly - for Light Oil

OIL MODULATING CAM

OIL METERING VALVE

PACKING GLANDOIL PRESSURE REGULATOR

OIL BURNER PRESSURE GAUGE

BACK PRESSURE ORIFICEOIL RETURN PRESSURE GAUGEOIL BURNER PRESSURE GAUGEOIL MODULATING CAM OIL METERING VALVE GLAND2-9

FUEL OIL THERMOMETER

OIL RETURN

OIL SUPPLY

MANUAL BY-PASS VALVEBACK PRESSURE VALVETO MAIN OIL

ORIFICED VALVE

SOLENOID VALVE

Figure: 2-18 Oil Control Valve Assembly -for Heavy Oil


7. Terminal Block (Figure 2-16): The central connectionpoint for the supply and return oil.

8. Fuel Oil Strainer (Not Shown): Prevents foreign matterfrom entering the burner system.

9 ection D of Chapter 2 for description ofponents.

1 alve (Not Shown): When a light oil pilotolenoid valve is provided to control flow

11

controller to create back pressure (100 and 200 seriesonly).`

12. Air Pump Module Assembly (Figures 2-19, 20 & 21):Provides the compressed air required to atomize the fueloil for proper combustion. The CB-LE air pump moduleis started automatically by the programmers sequence. Itincludes components described A-H.

A.Air Pump Motor: Drives the air pump and an aircooling fan. The motor is started and stoppedsimultaneously with the forced draft fan motor.

C. Air Filter:entering ai

D.Check Valve: Prevents lubricating oil and compressedair from surging back through the pump and air filterwhen the pump stops.

E. Air-Oil Receiver Tank: Holds a supply of oil forlubricating the air pump. The receiver tank alsoseparates lube oil from the atomizing air beforedelivery to nozzle.

F. Lube Oil Level Sight Glass: Indicates the level oflubricating oil in the air-oil receiver tank.

G.Lube Oil Cooling Coil: Cools the lubricating oilbefore it enters the air pump. A fan driven by the airpump motor circulates cooling air over the coil.

H.Lube Oil Fill Pipe and Strainer: Used when adding oilto the air-oil receiver tank.

13. Low Oil Pressure Switch (Optional): Switch contactsopen when the fuel oil pressure drops below selectedpressure. Switch will interrupt the limit circuit upon lossof sufficient fuel oil pressure for correct combustion.

14. Fuel Oil Pump (Not Shown): Transfers fuel oil from thestorage tank and delivers it under pressure to the burnersystem.

FB. Air Pump: Provides air for atomization of the fuel oil.

ABC

DE

F

G

H

A. AIR PUMP MOTORB. AIR PUMPC. AIR FILTERD. CHECK VALVE

E. AIR-OIL RECEIVER TANKF. LUBE OIL LEVEL SIGHT GLASSG. LUBE OIL COOLING COILH. LUBE OIL FILL PIPE

G

Figure: 2-20 Belt Driven Air Pump

(CB)

igure: 2-19 Air Pump (Primary Air) CB-LE (Optional CB

AIR INTAKE CONTROL VALVE2-10AIR FILTERFigure: 2-21 Belt Driven Air Pump Component Locations (CB)

)

COMBUSTION

AIR PUMP

DRIVE BELT HOUSING

AIR-OIL

LUBE OIL LEVEL SIGHT GLASS

AIR INLET

TANKRECEIVER

of fuel to the pilot nozzle. It is energized throughprogrammer contacts. It is deenergized to shut off pilot. Gas Pilot: See Sthe various com

0. Light Oil Pilot Vis furnished, a s The filter cleans the air supply prior tor pump.fuel flow after main flam

. Back Pressure Orifice: Areturn line immediatelye is ignited and established.

restriction located in the oil downstream of the fuel oil750-184

Bur er 2

F. ADDITIO

The oil heater (Figoil to the point wburned. Most heavreduce the viscosieither steam or hooperating with hot water will have additional controls notrepresented in Figure 2-22.

Heater Switch (Not Shown): Manually provides power to theoil heater system.

1. Oil Heater (Electric): Used for heating sufficient fuel oilfor low-fire flow during cold starts before steam or hotwater is available for heating. The heater must be turnedoff during extended boiler lay-up, or at any time the fueloil transfer pump is stopped.

2. Electric Oil Heater Thermostat: Senses fuel oiltemperature and energizes or deenergizes the electric oilheater to maintain required temperature of the fuel oil.

3. Steam Oil Heater Thermostat: Senses fuel oiltemperature and controls the opening and closing of thesteam heater valve to maintain the required temperature

supply tank.

6. Oil Inlet From Supply Tank: Heavy oil inlet from thesupply tank.

7. Steam Heater Check Valve: Prevents oil contaminationof the waterside of pressure vessel should any leakageoccur in the oil heater.

8. Steam Trap: Drains condensate and prevents loss ofsteam from the steam oil heater. Condensate must bepiped to a safe point of discharge.

9. Check Valve (Steam Heater Discharge): Prevents airentry during shutdown periods when cooling action maycreate vacuum within steam heater.

10. Steam Heater Pressure Regulator: Adjust to providereduced (usually less than 15 psi) steam pressure to the

16

17of the fuel oil.

4. Oil Heater Shell (Steam/Hot Water): Heats fuel oilthrough medium of steam or hot water. Electric heater is

1. OIL HEATER (ELECTRIC)2. OIL HEATER THERMOSTAT (STEAM)3. OIL HEATER THERMOSTAT (ELECTRIC)4. OIL HEATER SHELL5. OIL RETURN TO TANK6. OIL INLET FROM TANK7. CHECK VALVE8. STEAM TRAP9. CHECK VALVE

1 2 4 53

15

18750-184Figure: 2-22 Oil Heatinheater to properly maintain the required fuel oiltemperature. The regulator and the pressure gauge arenot furnished on 15 psi units.

11. Steam Heater Solenoid Valve: A normally open solenoidvalve opened by the steam oil heater thermostat to allow

10. STEAM HEATER PRESSURE REGULATOR11. STEAM HEATER SOLENOID VALVE12. STEAM PRESSURE GAUGE13. OIL RELIEF VALVE14. LOW OIL TEMPERATURE SWITCH15. OIL SUPPLY PRESSURE GAUGE16. OIL RETURNED FROM FUEL OIL CONTROLLER17. HEATED OIL TO BURNER18. FUEL OIL STRAINER

76 8

9

10

11121314ner Operation and Control ChaptNAL CONTROLS FOR HEAVY OIL

ure 2-22 Steam) is provided to heat heavyhere it can be effectively atomized andy oil heaters utilize an electric heater toty of the heavy oil until the point wheret water is available. Heavy oil heatershoused in the steam heater, but is housed separately on ahot water heater. Steam oil heaters on 15 psi boilersoperate at boiler pressure. Steam oil heaters furnished onhigh pressure boilers are to be operated at less than 15psi. Operation is accomplished with a steam pressureregulator valve.

5. Oil Return To Tank: Excess oil returned to the heavy oils2-11g Assembly (Steam)


G. CONTROLS FOR COMBINATION BURNERS ONLY

(1) Gas-Oil Switch (Figure 2-23): Burners equipped to burneither oil or gas include equipment for each fuel. The selectorswitch engages the appropriate interlocks and controls for gasor oil operation. Chapter 4 details the required mechanicalfunctions of each fuel system.

GAS / OILSELECTORflow of steam to the steam heater to maintain temperatureof fuel oil.

12. Steam Pressure Gauge: Indicates steam pressure enteringthe heater.

13. Oil Relief Valve: Allows release of excessive pressure tothe return side of the oil line piped to the tank.

14. Low-Oil-Temperature Switch: Thermostatic switch thatprevents burner from starting, or stops burner firing iffuel oil temperature is lower than required for oil burneroperation.

15. Oil Supply Pressure Gauge: Indicates fuel oil pressure inthe oil heater and supply pressure to the fuel oilcontrollers pressure regulator.

In addition to the components of the fuel oil controllermentioned in Section E, the following are used with a heavyoil fired burner.

A.High-Oil-Temperature Switch (Optional): Switchcontacts open when fuel oil temperature raises abovea selected temperature. Switch will interrupt the limitcircuit in the event fuel oil temperature rises above theselected point.

B. Hot Water Oil Heater Thermostat: Used on a hot waterboiler to sense fuel oil temperature and control thestarting and stopping of the booster water pump.

C. Booster Water Pump: Started and stopped by the hotwater thermostat to regulate the flow of hot waterthrough the hot water oil heater to maintaintemperature of fuel oil.

D.Fuel Oil Thermometer: Indicates temperature of fueloil being supplied to the fuel oil controller.

E. Back Pressure Valve: For adjustment of oil pressure onthe downstream side of the metering valve. Alsoregulates rate of return oil flow.

F. Oil Return Pressure Gauge: Indicates oil pressure onthe return side of the fuel oil controller.

G.Manual By-Pass Valve: Provided as a time saver inestablishing oil flow. When open, i t permitscirculation of oil through the supply and return lines.The valve must be closed prior to initial light off.

H.Orifice Oil Control Valve: Valve may be opened priorto start-up to aid in establishing fuel oil flow throughthe controller. The valve must be closed prior to initiallight off. Its disc has an orifice to permit a continuouscirculation of hot fuel oil through the controller.

I. Air Purge Valve: Solenoid valve opens simultaneouslywith closing of oil solenoid valve at burner shutdown,allowing compressed air to purge oil from the burnernozzle and adjacent piping. The oil is burned by the2-12H. COMBUSTION AIRAir for combustion of fuel (often referred to as secondaryair) is furnished by the forced draft fan (Figure 2-24) mountedin the boiler head. In operation, air pressure is built up in theentire head and is forced through a diffuser plate for athorough mixture with the fuel for proper combustion. Thesupply of secondary air to the burner is governed byautomatically throttling the output of the fan by regulating therotary air damper. The damper provides the proper amount ofair for correct ratio of air to fuel for efficient combustion at allfiring rates.

Figure: 2-23 Standard Control Panel

SWITCHdiminishing flame, which continues burning forapproximately 4 seconds after the oil solenoid valvecloses.

J. Air Purge Orifice Nozzle: Limits purging air to properquantity for expelling unburned oil at normal deliveryrate.

K.Air Purge Orifice Nozzle Filter: Filters the purging airof any particles that might plug the air purge orificenozzle.

L. Air Purge Check Valve: Valve check prevents fuel oilfrom entering the atomizing air line.

M.Air Purge Relay: When energized, controls operation

of air purge valve.750-184

Burner Operation and Control Chapter 2750-184

I. AUTOMATIC IGNITIONOil or gas burners are ignited by an interrupted-type pilot. Thepilot flame is ignited automatically by an electric spark.

The series 100 burner usually is equipped with a pilot firedwith light oil fuel. All other burners are equipped with a gasburning pilot. In the case of a combination burner, the gaspilot is used to ignite either the main gas flame or the oilflame. Either pilot serves the same function. Unless exceptionis taken in the text, the term pilot is used interchangeably.

At the beginning of the ignition cycle, and governed by theprogram relay, the pilot solenoid valve and ignitiontransformer are simultaneously energized.

The ignition transformer supplies high voltage current for theigniting spark. A gas pilot has a single electrode and a sparkarcs between the tip of the electrode and the wall of the tubesurrounding it. A light oil pilot has two electrodes and the arcis between their tips. The pilot solenoid valve and thetransformer are deenergized after main flame is ignited andestablished.

Fuel for the gas pilot is supplied from the utilitys main, orfrom a tank (bottle) supply. Secondary air flows into andmixes with the pilot gas stream to provide an adequate flame.

Figure: 2-24 Secondary Air Flow Diagram (CB-LE)Insurance regulations may require two gas pilot solenoidvalves with a normally open vent valve between them. Thevent valve closes when the gas pilot valves open, and openswhen the gas pilot valves shut to vent gas, should any bepresent in the pilot line during the deenergized period of thegas pilot valves.

Fuel for a light-oil pilot is provided from the line that suppliesoil under pressure for the main flame. A solenoid actuatedvalve controls flow of oil to the pilot nozzle. The valve isenergized simultaneously with the ignition transformer at thebeginning of the ignition cycle and is deenergized after mainflame is ignited and established.

J. ATOMIZING AIRAir for atomizing the fuel oil (often referred to as primaryair) is pumped by the air pump into the air-oil receiver tankand delivered under pressure through a manifold block to theoil burner nozzle.

The atomizing air mixes with the fuel oil just prior to the oilleaving the nozzle.

Atomizing air pressure is indicated by the air pressure gaugeon the burner gun.

Air pressure from the pump also forces sufficient oil from thetank to the pump bearings to lubricate them and also toprovide a seal and lubrication for the pump vanes. As a result,the air delivered to the tank contains some lube oil; however,most of it is recovered through baffles and filters in the tankbefore the air passes to the burner.

Some of the primary air is also used to assist the oil pressureregulators of the fuel oil controller. Further explanation isgiven in chapter 5.

K. OIL FUEL FLOW - LIGHT OILThe oil fuel flow system schematic is shown in Figure 2-25.Oil flow is indicated by arrows and the pertinent controls arecalled out. Fuel oil is delivered into the system by a supplypump which delivers part of its discharge to the oil burner.Excess oil is returned to the oil storage tank through the fueloil relief valve and oil return line. Normally the pumpoperates only while the burner is in operation, although apositioning switch is often provided so that either continuousor automatic pump operation can be obtained.

The oil flows through a fuel oil strainer to prevent any foreignmaterial from flowing through the control valves and nozzle.The fuel oil controller contains in a single unit, a meteringvalve, a regulator, and a gauge required to regulate thepressure and flow of oil to the burner. The adjustable regulator2-13

controls the pressure. To assist in the regulation, back


2-14PRESSURE GAUGENOZZLE AIR750-184

Figure: 2-25 Schematic Diagram for Light Oil Flow

FUEL OILSTRAINER

OIL SUPPLYPRESSURE

GAUGE

OIL RELIEFVALVE

FUEL OILSUPPLY PUMP

FUEL OILSTRAINER

NOT SUPPLIEDBY CLEAVER BROOKS

TEE

VALVEGAUGE

SHUTOFFVALVE

REGULATOROIL PRESSURE

OIL MODULATINGCAM

PRESSURE GAUGEOIL BURNER

CONTROLLERFUEL OIL

VALVEOIL SOLENOID

BACK PRESSURE ORIFICEOIL RETURN

RECEIVER TANKAIR OIL

LUBE OIL

PROVING SWITCHATOMIZING AIR

LUBE OILSTRAINER

SWING CHECK VALVE

AIR STRAINER

ATOMIZING AIR

MANIFOLDBLOCK

OIL BURNER NOZZLE

INLETOIL

FUEL

AIR PUMP

RETURNFUEL OIL

VACUUMCHECK

PRIMING

VALVEOIL METERING

ATOMIZING AIR PRESSUREFEED BACK CONTROL TUBING


750-184

OIL HEATE(ELECTRIC

FUEL OILSTRAINER

OP

* THESEPRESS2-15

Figure: 2-26 Schematic Diagram for No. 6 Heavy Oil Flow (Steam-Electric Heater)

R) OIL HEATER

THERMOSTAT(STEAM)

OIL HEATERSHELL

IL SUPPLYRESSUREGAUGE

OIL HEATERTHERMOSTAT(ELECTRIC)

OIL RELIEFVALVE

STEAM HEATERPRESSURE GAUGE

STEAM HEATER

SOLENOID VALVESTEAM PRESSURE

REGULATOR

CHECK VALVESTEAM STRAINER

STEAM SHUTOFFVALVE

CHECKVALVE STEAM TRAP

FUEL OILSUPPLY PUMP FUEL OIL

STRAINER

NOT SUPPLIEDBY CLEAVER BROOKS

PRIMING TEE

CHECK VALVE

VACUUM GAUGE

SHUTOFF

VALVE

NOTE: CONDENSATE FROM STEAMTRAP MUST BE WASTED AND PIPEDTO A SAFE POINT OF DISCHARGE.

BY-PASSMANUAL

VALVE

FUEL OILTHERMOMETER

REGULATOROIL PRESSURE

OIL MODULATINGCAM

PRESSURERELIEF VALVE

OIL RETURNPRESSURE

GAUGE

ORIFICEDVALVE

OIL BURNERPRESSURE

GAUGE

VALVEOIL METERING

SWITCHTEMPERATURE

LOW OIL

CONTROLLERFUEL OIL

VALVEOIL SOLENOID

VALVEAIR PURGE

CHECK VALVEAIR PURGE

CHECK VALVEAIR PURGE

RECEIVER TANKAIR OIL

LUBE OIL

PROVING SWITCHATOMIZING AIR

LUBE OILSTRAINER

SWING CHECK VALVE

AIR STRAINER

ATOMIZING AIR

MANIFOLDBLOCK

PRESSURE GAUGENOZZLE AIR

OIL BURNER NOZZLE

ITEMS ARE USED ON HIGHURE GENERATORS ONLY

INLETOIL

FUEL

AIR PUMP

RETURNFUEL OIL

STEAM INLET

ATOMIZING AIR PRESSUREFEEDBACK CONTROL TUBING

Chapter 2 Burner Operation and Controlpressure is created by an orifice nozzle located in the oilreturn line immediately downstream of the fuel oil controller.

The programming relay energizes or deenergizes the solenoidoil valves to permit or cut off oil flow to the burner. Twovalves, operating simultaneously, are used. The valves areclosed when deenergized. They cannot be opened (energized)unless the combustion air proving switch and the atomizingair proving switch are closed. The two switches are satisfied,respectively, by sufficient combustion air pressure from theforced draft fan and pressurized air from the air pump.

The oil flow to the burner is controlled by the movement ofthe metering stem in the oil metering valve, which varies theflow to meet load demands. The metering valve and the airdamper are controlled simultaneously at all times by themodulating motor to proportion combustion air and fuel forchanges in load demand.

L. OIL FUEL FLOW - HEAVY OILThe oil fuel flow and circulating system is shown inschematic diagram form in Figures 2-26. The pertinentcontrols are called out and the oil flow is indicated by arrows.

Fuel oil is delivered into the system by the fuel oil supplypump which delivers part of its discharge to the oil heater. Theremainder of the fuel oil returns to the oil storage tankthrough a fuel oil relief valve and oil return line.

The combination electric and steam oil preheater is controlledby thermostats. The electric oil heater thermostat energizesthe electric heater, which is provided to supply heated oil oncold starts. The steam heater thermostat controls operation ofthe steam solenoid valve to permit a flow of steam to theheater when steam is available.

A hot water boiler is equipped to heat the oil with hot waterfrom the boiler, unless other preheating equipment is utilized.The electric heater, which is housed separately, is sized toprovide heated oil on a cold start. The hot water thermostatcontrols the operation of a pump that supplies hot water to theoil heater when hot water is available.

The heated oil flows through a fuel oil strainer to prevent anyforeign matter from entering the control valves and nozzle.

The fuel oil controller contains, in a single unit, the necessaryvalves, regulators and gauges to regulate the pressure andflow of oil to the burner.

The program relay energizes or deenergizes the solenoid oilvalve to permit or cut off oil flow to the burner. The oilsolenoid is closed when deenergized. It cannot be opened(energized) unless the combustion air proving switch, theatomizing air proving switch, and the low oil-temperature andany pressure switches are closed. They are satisfied,respectively, by sufficient combustion air pressure from theforced draft fan, pressurized air from the air pump andsufficient oil temperature and pressure.

Oil flow to the burner is controlled by the movement of themetering stem of the oil metering valve, which varies the flowto meet load demands. The metering valve and the air damperare controlled simultaneously at all times by the modulatingmotor to proportion combustion air and fuel for changes inload demand.

Oil is purged from the burner gun upon each burnershutdown. The air purge solenoid valve opens as the fuelvalve closes, diverting atomizing air through the oil line. Theair assures a clean nozzle and line for subsequent restart.

M. GAS FUEL FLOWMetered gas from the utility flows through the pressureregulator at a reduced pressure suitable to burnerrequirements, through the main gas shutoff cock, main gasvalve(s), and modulating butterfly gas valve to the non-premix orifice-type burner.

The main gas valve is of the normally closed type, and isopened (energized) in proper sequence by the programmingrelay.

The butterfly gas valve modulates the flow of gas from lowthrough high fire settings. The position of the butterfly valvedisc is governed by the gas modulating cam. The butterfly gasvalve , and the a i r control damper are control ledsimultaneously by the modulating motor to proportioncombustion air and fuel for changes in load demand.

The gas flow rate required for rated burner input dependsupon the heating value (Btu/cubic foot) of the gas supplied.The gas pressure regulator adjusts the gas pressure (flow rate)to the entrance of the gas train. The regulator is not alwayssupplied with the burner, but may be provided by others.

The main gas valves cannot be energized (opened) unless thecombustion air proving switch is closed to indicate asufficient supply of combustion air. The low gas pressure andhigh gas pressure switches must be closed to prove sufficient,but not excessive, gas fuel pressure.

N. MODULATING FIRINGThe modulating motor, through a linkage arrangement(Figure 2-27), controls the air damper and the butterfly gasvalve, or the oil metering valve, to maintain a constant air/fuelratio throughout the firing range.

During burner operation, the motor is controlled by amodulating pressure control on a steam boiler, or by amodulating temperature control on a hot water boiler. Amanually operated potentiometer is provided to permitpositioning of the motor at the desired burner firing rate. Thepotentiometer is used primarily for initial or subsequentchecking and setting of fuel input. Normal operation shouldbe with the manual-automatic switch in the automaticposition and under the control of the modulating control.2-16 750-184

Burner Operation and Control Chapter 2750-184 2-17

The modulating motor (commonly called a damper motor) isreversible. It has an internal limit switch that restricts shaftrotation to 90. During normal operation the motor will movein either direct

750-184 CB_CBLE 125-200 HP (rev 1998)

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