Basic Ref Piping[1].ppt

WELCOMEWELCOME

OUR GOALS FOR THE DAYOUR GOALS FOR THE DAY

• Understanding Refrigeration Piping– Learn by doing, using piping examples

• Review troubleshooting examples

LET’S DISCUSS LET’S DISCUSS THE MATERIALTHE MATERIAL

Refrigerant Piping

Residential Piping Design

Form Number

690.01-AD1V

&

Worksheet

690.01-AD1.1V

Introduction (From the App. Guide)

The tables and application data in this publication will help you to better apply split system cooling and heat pump systems to achieve maximum efficiency and performance, improved reliability, and greater customer satisfaction. This guideline includes information for:

· General piping practices

· Vapor and liquid line sizing

· Total line length limitations

· Elevation limitations

· Orifice changes

· System charging

· Special considerations for long line lengths

General Guidelines· Support all refrigerant lines at minimum intervals (4 feet) with suitable hangers and brackets.

· Slope horizontal suction lines on cooling only systems approximately 1 inch every 20 feet toward the outdoor unit to facilitate proper oil return. Since the flow of refrigerant is bi-directional on heat pumps, horizontal vapor lines should be level.

Refrigerant Line Sizing

Line Length

• Use Factory Connection Size Up To 25’– Factory charge to 15’– Over 15’ refer to “LINE CHARGE TABLE”

• Over 25’-Refer to Long Line Application– Form 690.01-AD1V

Piping Do’s & Don’ts

• Use hard Solder• Use Nitrogen• Remove Schraders• Do Not Over Heat• Preheat Joint • Do NOT open Service

Valves• Liquid Line Insulation?

• Insulate Vapor Line– 3/8” Close Cell

Insulation

• Support lines– Every 4’

• Slope Horizontal Vapor Lines– 1” for every 20’

Towards Compressor

(Cooling ONLY)

Total Line Length

equals

Horizontal Runs + Vertical Runs

Total Line Equivalent Length

Equals

Horizontal Runs + Vertical Runs

PLUS the equivalent of the Fittings

Vapor Line Considerations• 1000 fpm minimum Velocity on Horizontal lines.

– Oil Return

• 700 fpm minimum Velocity on Vertical lines.– Oil Return

• 3000 fpm maximum Velocity to avoid:– Refrigerant Noise– Vibrating lines, especially at elbows

• Pressure Drop Causes Capacity Loss– A 1 lb. pressure drop = 1% of capacity Loss– Our recommendation is a maximum 3 lbs. drop

• Oil Traps– Outdoor above indoor, use traps as per guidelines– Indoor above outdoor, use inverted trap

Oil TrapsCooling or Heat Pumps

• Design– (2) 45 Degree Short Elbows

– (1) 90 Degree Short Elbow

• Outdoor Unit Above Indoor– Trap Located at Bottom of Riser

– Lifts Between 50’-100’ 2 nd Trap at Mid-Point

– Lifts Over 100’, Trap at 1/3 rd Intervals

• Indoor Unit Above Outdoor– Inverted Vapor Regardless of Line Length

– Observe Coil DesignP fac

Oil droplets Returning to Compressor

Any riser greater Any riser greater than 3’ in height than 3’ in height must include a trap.must include a trap.

Oil Trap2-Short L’s1-Long L

Inverted Trap

Whenever the Evaporator is Above the Condenser

Where inverted traps are not an option, a Liquid Line Solenoid Valve will help prevent refrigerant migration. NOTE: If a high M.O.P. TXV is used, a LLSV is not necessary

Pressure Drop Occurs

Whenever the Evaporator

is Above the Condenser

Concerns:A. Loss of Subcooling ? ? ?

B. Does the Metering Device Need Changed ? ? ?

Liquid Line Considerations

• 30 lb Max (40 lb com)Total System Pressure Drop– 30 lb (40 lb com) Drop consists of:

• Fictional Loss of Pipe• Liquid Riser = 1/2 lb pressure drop Per Foot• Liquid Fall = 1/2 lb pressure gain Per Foot

• 3 lb Pressure Drop = 1 Degree Sub-Cooling Loss• High pressure may force an Orifice Change?• 50’ Elevation Difference Max ( Heat Pump)

Liquid Line Considerations

NO! extra oil needed

Liquid Line Gain

Condenser is above

the Evaporator

Liquid Line Loss

Condenser is below

the Evaporator

Orifice Size & Adder Chart

Application Data

Application Data

Additional Refrigerant

In many applications, additional refrigerant will have to be added to the system. The actual amount of charge that must be added is determined by adding the following:

1. The indoor coil charge adjustment from the Product Tech Guide. This is always a predetermined amount based on the outdoor unit/indoor coil combination being used.

2. The additional charge required for the interconnecting pip-ing. This is dependent on the type of unit being used (i.e., sweat or quick-connect ) and the size of the vapor and liquid lines.

3. Refer to Table #6 for both Suction and Vapor

Additional Requirements

If not provided as standard features, the following items are required when measured piping lengths exceed fifty feet:

1. Low Voltage Start Kit (2SA06701006) - single phase units on 208V application.

2. Off Cycle Timer (2TD08700124) - if item 1 is used.

3. Crankcase Heater (025-19961-001) - except units with a scroll compressor.

On cooling only systems with measured piping lengths greater than seventy-five (75) feet, one of the accumulators in Table 8 must be field installed near the outdoor unit. The accumulator should be sized based on total system charge.

Time for some examples (and your turn to work)