Fan-Powered Parallel 75 VAV-PRC005-EN Model Number Description 76 Selection Procedure 77 - 79 General Data – Setting Guidelines 80 Performance Data – Pressure Requirements 81 Performance Data – Fan Curves 82 - 85 Performance Data – Hot Water Coil 86 - 87 Performance Data – Electrical Data 88 Performance Data – Acoustics 89 - 93 Dimensional Data 94 - 96 Mechanical Specifications 97 - 99 Table of Contents
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Fan-PoweredParallel
75VAV-PRC005-EN
Model Number Description 76
Selection Procedure 77 - 79
General Data – Setting Guidelines 80
Performance Data – Pressure Requirements 81
Performance Data – Fan Curves 82 - 85
Performance Data – Hot Water Coil 86 - 87
Performance Data – Electrical Data 88
Performance Data – Acoustics 89 - 93
Dimensional Data 94 - 96
Mechanical Specifications 97 - 99
Table ofContents
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ModelNumberDescription
Parallel Fan-powered VAVTerminal UnitsThe features of the parallel fan-powered VAV terminal units aredescribed by the product categoriesshown below in bold. Within eachcategory the options availableare listed.
CONN Controls & Heat Connection SideLeft Left sideHWCL Hot Water Coil1ROW One-row hot water coil2ROW Two-row hot water coilFUSE Power FuseWith Power fuseVOLT Electric Heater Voltage2081 208 Volt, 1-Phase2083 208 Volt, 3-Phase2401 240 Volt, 1-Phase2771 277 Volt, 1-Phase3471 347 Volt, 1-Phase4801 480 Volt, 1-Phase4803 480 Volt, 3-Phase5753 575 Volt, 3-PhaseSTGE Electric Heater Stage1 1 stage of heat2 2 stages of heat – equal3 3 stages of heat – equalHTKW Electric Heater Kilowatts0.5 0.5 kW1.0 1.0 kW1.5 1.5 kW2.0 2.0 kW2.5 2.5 kW3.0 3.0 kW3.5 3.5 kW4.0 4.0 kW4.5 4.5 kW5.0 5.0 kW5.5 5.5.kW6.0 6.0 kW6.5 6.5 kW7.0 7.0 kW7.5 7.5 kW8.0 8.0 kW9.0 9.0 kW10.0 10.0 kW11.0 11.0 kW12.0 12.0 kW13.0 13.0 kW14.0 14.0 kW15.0 15.0 kW16.0 16.0 kW17.0 17.0 kW18.0 18.0 kW20.0 20.0 kWCNTR Electric Heater ControlMAGN 24 volt magnetic contactorsMERC 24 volt mercury contactorsPEMA P.E. w/ magnetic contactorsPEME P.E. w/ mercury contactorsDISW Power Disconnect SwitchWITH Power disconnect switchAFSW Electric Heater Air flow SwitchWITH Electric heater airflow switch
VPCF
VPWF
VPEF
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SelectionProcedure
This section describes the elementsand process required to properly selectparallel fan-powered VAV terminals,and includes a specific example. Theselection procedure is iterative innature which makes computerselection desirable.
Selection of fan-powered VAVterminals involves four elements:
�Air valve selection�Heating coil selection� Fan size and speed selection�Acoustics
Air Valve Selection
Provided in the performance datasection of the catalog is the Wide-OpenAir Pressure Drop vs. Airflow curve. Toselect an air valve, locate the requireddesign cooling airflow and find itsvertical intersection with the smallestair valve size that has air pressure dropequal to or lower than the maximumwide-open air pressure droprequirement.
Heating Coil Selection
Supply Air TemperatureThe first step required when selecting aheating coil is to determine the heatingsupply air temperature to the space,calculated using the heat transferequation. Air temperature difference isdefined as the heating supply airtemperature to the space minus thewinter room design temperature. Thezone design heat loss rate is denotedby the letter Q. Supply air temperatureto the space equals the leaving airtemperature (LAT) for the terminal unit.
Coil Leaving Air TemperatureOnce the terminal unit LAT isdetermined, the heating requirementsfor the coil can be calculated. Theleaving air temperature for the coil of aparallel fan-powered terminal unitvaries based on the type of unitinstalled heat being selected.
Electric coil LAT equals terminal unitLAT because the coil is located on theunit discharge. Hot water coils,however, are located on the enteringair side of the fan. In this case, coil LATis calculated using a mixing equation.Given the unit heating airflow and LAT,minimum primary airflow at its supplyair temperature, and the volume ofheated plenum air, the leaving airtemperature for the hot water coil canbe determined (see the unit selectionexample that follows for more details).
Coil Entering Air TemperatureThe entering air temperature (EAT) tothe coil also varies based on the coilposition on the unit.
Electric coil EAT equals thetemperature of blended primary airand plenum air because the coil is in ablow-thru configuration. The unit hotwater coil configuration is draw-thru,therefore, EAT equals the plenumair temperature.
Capacity RequirementOnce both coil EAT and LAT aredetermined, the heat transfer (Q) forthe coil must be calculated using theheat transfer equation. For electric heatunits, the Q value must be convertedfrom Btu to kW for heater selection.The required kW should be comparedto availability charts in the performancedata section for the unit selected. Forhot water heat units, reference thecapacity charts in the performance datasection for the required heat transfer Qand airflow to pick the appropriate coil.
Fan Size and Selection
Fan AirflowFan airflow is determined bycalculating the difference betweenthe unit design heating airflow andminimum primary airflow.
Fan External Static PressureFan external static pressure is the totalresistance experienced by the fan,
which may include downstreamductwork and diffusers, heating coils,and sound attenuators. As total airflowvaries so will static pressure, makingcalculation of external static pressuredependent on unit type.
In many applications of parallelterminals, a minimum primary airflowmust be maintained to meetventilation requirements. This primaryairflow contributes to the totalresistance experienced by the fan andshould be accounted for in allcomponents downstream of the fanitself, including electric coils. Hot watercoils are positioned on the fan inlet andare not affected by the additionalprimary airflow. The static pressureresistance experienced by the fan dueto the hot water coil is based on fanairflow only, not the totalheating airflow.
SelectionOnce fan airflow and external staticpressure are determined, reference thefan curves in the performance datasection. Cross plot both airflow andexternal static pressure on eachapplicable graph. If the point isbetween the high and low ranges forthe fan, that fan size will work.
It is common to identify more thanone fan that can meet the designrequirements. Typically, selectionbegins with the smallest fan availableto meet capacity. If this selectiondoes not meet acousticalrequirements, upsizing the fan andoperating it at a slower speed can bedone for quieter operation.
Acoustics
Air Valve Generated NoiseTo determine the noise generated bythe air valve, two pieces of informationare required; design airflow and designair pressure drop. The design airpressure drop is determined by takingthe difference between design inletand static pressure (the valve’s most
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SelectionProcedure
over-pressurized condition) and externalstatic pressure at design cooling flow.This represents a worst-case operatingcondition for the valve.
Fan Generated NoiseTo determine fan noise levels, fanairflow, external static pressure andspeed information is required.
Evaluation ElementsFor parallel fan-powered terminal units,the air valve and fan operation must beevaluated separately because theseoperations are not simultaneous.
Access the appropriate acousticstable(s) of the catalog and determinethe sound power and NC prediction forboth the discharge and radiated paths. Itis important to understand thatdischarge air noise is generally not aconcern with fan-powered terminals.Radiated noise from the unit casingtypically dictates the noise level ofthe space.
If the entire unit or any element of it isgenerating noise in excess of the NoiseCriteria requirements, the size of theappropriate portion of the terminalshould be increased. Because theselection procedure is iterative, careshould be taken by the designer toconfirm that the change in selectiondoes not affect other elements of theunit or system design.
Selection Example—
Parallel With Hot Water Heat
Air Valve SelectionRequired Information:
Design cooling airflow: 1000 cfmMaximum wide-openair pressure drop: 0.25 in. wg
Choose a size 10 air valve with wide-open air pressure drop of 0.05 in. wg
Heat Transfer Equation (Btu)Q = 1.085 x Cfm x D Temperature
For the heating zone, the temperaturedifference is the zone supply airtemperature (SAT) minus the winterroom design temperature.
20000 Btu = 1.085 x 600 x (SAT - 68ºF)SAT = 98ºF
Because the hot water coil is on theplenum inlet of a parallel fan-poweredunit, the unit supply air temperature isequal to the mix of the heated plenumair from the fan and the minimumprimary airflow.
600 cfm x 98ºF =200 cfm x 55ºF +(600 cfm - 200 cfm) x Coil LAT
Coil LAT = 121ºF
For the heating coil, the temperaturedifference is the calculated coil LATminus the coil EAT (Plenum AirTemperature).Coil Q = 1.085 x 400 x (121-70) =
Design airflow: 400 cfmDownstream static pressureat design airflow: 0.25 in. wg
Fan external static pressure equalsdownstream static pressure (ductworkand diffusers) plus coil static pressure.The coil static pressure that the fanexperiences is at the fan airflow(400 cfm). The downstream staticpressure the fan experiences is at fanairflow plus minimum primary airflow.The sum of fan airflow and minimumprimary airflow (600 cfm) is less thandesign airflow (1000 cfm) and thereforethe 0.25 in. wg downstream staticpressure at design airflow must beadjusted for the lower heating airflow.
Using Fan Law Two:Heating Downstream Static Pressure =(600/1000)2 x 0.25 = .09 in. wg
A size 02 fan has the capability to deliverapproximately 650 cfm at 0.09downstream static pressure.
AcousticsRequired Information:
Design inlet static press.: 1.0 in. wgNC criteria: NC-35
The selection is a VPWF Parallel Fan-powered Terminal Unit, primary air valvesize 10, parallel fan size 02, with a 2-rowhot water coil.
Determine the casing radiated noiselevel because it typically dictates thesound level (NC) of the space. With aparallel unit, two operating conditionsmust be considered, design cooling anddesign heating.
Design Cooling (1000 cfm). The closesttabulated condition (1100 cfm at1.0 in.wg ISP) has the followingtabulated results:
Parallel Fan-Powered Unit withElectric Heat
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Design Heating (200 cfm valve,400 cfm fan). The closest tabulatedcondition (390 fan cfm at 1.0 in. wg ISP)has the following tabulated results:
The predicted NC level for designcooling is NC-31 and for design heatingis NC-31. If the catalog path attenuationassumptions are acceptable, this unitmeets all of the design requirementsand the selection process is complete.Computer SelectionThe advent of personal computershas served to automate manyprocesses that were previouslyrepetitive and time-consuming. Oneof those tasks is the proper scheduling,sizing, and selection of VAV terminalunits. The Trane Company hasdeveloped a computer program toperform these tasks. The software iscalled the Trane Official ProductSelection System (TOPSS).The TOPSS program will take the inputspecifications and output the properlysized VariTrane VAV terminal unit alongwith the specific performance for thatsize unit.The program has several required fields,denoted by red shading on the TOPSSscreen, and many other optional fieldsto meet the criteria you have. Requiredvalues include maximum and minimumairflows, control type, and model. Ifselecting models with reheat, you willbe required to enter information tomake that selection also. The user isgiven the option to look at all theinformation for one selection on onescreen or as a schedule with the otherVAV units on the job.The user can select single-duct, dual-duct, and fan-powered VAV boxes withthe program, as well as most otherTrane products, allowing you to selectall your Trane equipment with onesoftware program.The program will also calculate soundpower data for the selected terminalunit. The user can enter a maximumindividual sound level for each octaveband or a maximum NC value. Theprogram will calculate acoustical datasubject to default or user suppliedsound attenuation data.
SelectionProcedure
Schedule ViewThe program has many time-saving features such as:� Copy/Paste from spreadsheets like Microsoft® Excel� Easily-arranged fields to match your schedule� Time-saving templates to store default settings
The user can also export the Schedule View to Excel to modify and put into a CADdrawing as a schedule.
Specific details regarding the program, its operation, and how to obtain a copy of itare available from your local Trane sales office.
Rearrange what fields you seeand in what order with a fewclicks of a button.
Required entry fields (in Redon TOPSS screen).
NOTE: Use the same procedures for selecting Low-Height Parallel Fan-PoweredUnits as used for selecting Parallel Fan-Powered Units
Octave 2 3 4 5 6 7 NCBand
Sound 67 58 56 53 48 44 20Power
Octave 2 3 4 5 6 7 NCBand
Sound 71 67 64 65 62 54 24Power
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General Data—SettingGuidelines
Primary Airflow Control Factory Settings – I-PControl Air Valve Cataloged Maximum Setting Minimum Setting Constant Volume
Notes:1. Fouling Factor = 0.000252. The off-coil temperature of the hot water coil on parallel fan-powered units must not exceed 140°F.3. The following equations may be used in calculating Leaving Air Temperature (LAT) and Water Temperature Difference (WTD).4. Capacity based on 70°F entering air temperature and 180°F entering water temperature. Refer to correction factors for
different entering conditions.
Temperature Correction Factors for Water Pressure Drop (ft)
Average Water Temperature 200 190 180 170 160 150 140 130 120 110Correction Factor 0.970 0.985 1.000 1.020 1.030 1.050 1.080 1.100 1.130 1.150
Temperature Correction Factors for Coil Capacity (MBH)
Entering Water Minus Entering Air 40 50 60 70 80 90 100 110 120 130Correction Factor 0.355 0.446 0.537 0.629 0.722 0.814 0.907 1.000 1.093 1.187
LAT = EAT + MBH x 921.7CFM WTD = EWT - LWT = 2 x MBH
GPM(( ) )
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PerformanceData—Hot WaterCoil (SI)
Notes:1. Fouling Factor = 0.000252. The off-coil temperature of the hot water coil on parallel fan-powered units must not exceed 60°C.3. The following equations may be used in calculating Leaving Air Temperature (LAT) and Water Temperature Difference (WTD).4. Capacity based on 21°C entering air temperature and 82°C entering water temperature. Refer to correction factors for
* Not available with 240/1** Three stages of electric heat available only with pneumatic controls.
Notes:1. Coils available with 24-VAC magnetic or mercury contactors, load carrying P.E. switches, and P.E. switch with magnetic or mercury contactors.2. Available kW increments are by 0.5 from 0.5 kW to 8.0 kW, by 1.0 kW from 9.0 to 18.0 kW, and by 2.0 kW from 18.0 to 20.0 kW.3. Each stage will be equal in kW output.4. All heaters contain an auto thermal cutout and a manual reset cutout .5. The current amp draw for the heater elements is calculated by the formula below.
Notes:1. Electric Heat Units - Units with Primary Voltage of 208/60/1,
208/60/3, or 240/60/1 use 115 VAC fan motors.2. Electric Heat Units - Units with Primary Voltage of 277/60/1,
480/60/1 or 480/60/3 use 277 VAC fan motors.3. Electric Heat Units - Units with Primary Voltage of 347/60/1 or
575/60/3 use 347 VAC fan motors.4. Values are for standard, single-speed, permanent split capacitor
type motors. Consult factory for non-standard motorperformance.
Notes:1. All data are measured in accordance with Industry Standard ARI 880-98.2. All sound power levels, dB re: 10-12 Watts.
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PerformanceData—Acoustics
Notes:1. “–“ represents NC levels below NC 15.2. NC Values are calculated using ARI 885-98, Type 2 –
Mineral Fiber Insulation.
ARI 885-98 DISCHARGE TRANSFER FUNCTION ASSUMPTIONS:Octave Band
2 3 4 5 6 7
Small Box (< 300 cfm) -25 -28 -38 -53 -58 -31Medium Box (300-700 cfm) -27 -29 -39 -51 -53 -33Large Box (> 700 cfm) -29 -30 -40 -51 -51 -35Note: Subtract from terminal unit sound power to determine dischargesound pressure in the space.
ARI 885-98 RADIATED TRANSFER FUNCTION ASSUMPTIONS:Octave Band
2 3 4 5 6 7
Type 1 – Glass Fiber -19 -19 -21 -25 -29 -35Type 2 – Mineral Fiber Insulation -18 -19 -20 -26 -31 -36Type 3 – Solid Gypsum Board -23 -26 -25 -27 -27 -28Note: Select the ceiling type which most closely represents theapplication. Next, subtract from terminal unit sound power to determineradiated sound pressure in the space.
Fan Only Sound PowerDischarge Sound Power (dB) Radiated Sound Power (dB)
Notes:1. “–“ represents NC levels below NC 15.2. NC Values are calculated using ARI 885-98, Type 2 – Mineral Fiber Insulation..
ARI 885-98 DISCHARGE TRANSFER FUNCTION ASSUMPTIONS:Octave Band
2 3 4 5 6 7
Small Box (< 300 cfm) -25 -28 -38 -53 -58 -31Medium Box (300-700 cfm) -27 -29 -39 -51 -53 -33Large Box (> 700 cfm) -29 -30 -40 -51 -51 -35Note: Subtract from terminal unit sound power to determine dischargesound pressure in the space.
ARI 885-98 RADIATED TRANSFER FUNCTION ASSUMPTIONS:Octave Band
2 3 4 5 6 7
Type 1 – Glass Fiber -19 -19 -21 -25 -29 -35Type 2 – Mineral Fiber Insulation -18 -19 -20 -26 -31 -36Type 3 – Solid Gypsum Board -23 -26 -25 -27 -27 -28Note: Select the ceiling type which most closely represents theapplication. Next, subtract from terminal unit sound power to determineradiated sound pressure in the space.
CASING22-gage galvanized steel. Hangerbrackets, side access, and filter whichis on the plenum inlet are providedas standard.
AGENCY LISTINGThe unit is UL and Canadian ULListed as a room air terminal unit.Control # 9N65.
ARI 880 Certified.
INSULATION
1/2" (12.7 mm) Matte-facedInsulation—The interior surface of theunit casing is acoustically andthermally lined with ½-inch, 1.75 lb/ft3
(12.7 mm, 28.03 kg/m3) compositedensity glass fiber with a high-densityfacing of 4.0 lb/ft3 (64 kg/m3). Theinsulation R-Value is 1.9. The insulationis UL listed and meets NFPA-90A andUL 181 standards. There are noexposed edges of insulation (completemetal encapsulation).
1" (25.4 mm) Matte-facedInsulation—The interior surface of theunit casing is acoustically andthermally lined with 1 inch, 1.55 lb/ft3
(25.4 mm, 24.8 kg/m3) compositedensity glass fiber with a high-densityfacing of 4.0 lb/ft3 (64 kg/m3). Theinsulation R-Value is 3.85. Theinsulation is UL listed and meetsNFPA-90A and UL 181 standards. Thereare no exposed edges of insulation(complete metal encapsulation).
1/2" (12.7 mm) Foil-facedInsulation—The interior surface of theunit casing is acoustically andthermally lined with ½-inch, 2.0 lb/ft3
(12.7 mm, 32.04 kg/m3) density glassfiber with foil facing. The insulationR-Value is 2.2. The insulation is ULlisted and meets NFPA-90A and UL 181standards as well as bacteriologicalstandard ASTM C 665. There are noexposed edges of insulation (completemetal encapsulation).
1" (25.4 mm) Foil-facedInsulation—The interior surface ofthe unit casing is acoustically andthermally lined with 1-inch, 2.0 lb/ft3
(25.4 mm, 32.04 kg/m3) density glassfiber with foil facing. The insulation R-Value is 4.3. The insulation is UL listedand meets NFPA-90A and UL 181standards as well as bacteriologicalstandard ASTM C 665. There are noexposed edges of insulation (completemetal encapsulation).
1" (25.4 mm) Double-wallInsulation—The interior surface ofthe unit casing is acoustically andthermally lined with a 1-inch, 2.1 lb./ft3
(25.4 mm, 33.6 kg/m3) compositedensity glass fiber with high-densityfacing. The insulation R-value is 3.0. Theinsulation is UL listed and meets NFPA-90A and UL 181 standards. Theinsulation is covered by an interiorliner made of 26-gage galvanized steel.All wire penetrations are covered bygrommets. There are no exposededges of insulation (complete metalencapsulation).
3/8" (9.5 mm) Closed-cellInsulation—The interior surface ofthe unit casing is acoustically andthermally lined with 3/8-inch, 4.4 lb/ft3
(9.5 mm, 40.0 kg/m3) closed-cellinsulation. The insulation is UL listedand meets NFPA-90A and UL 181standards. The insulation has anR-Value of 1.4. There are no exposededges of insulation (complete metalencapsulation).
PRIMARY AIR VALVE
Air Valve Round—The primary airinlet connection is an 18-gagegalvanized steel cylinder sized to fitstandard round duct. A multiple-point,averaging flow sensing ring isprovided with balancing taps formeasuring +/-5% of unit catalogedairflow. An airflow-versus-pressuredifferential calibration chart is provided.The damper blade is constructed of aclosed-cell foam seal that ismechanically locked between two 22-gage galvanized steel disks. Thedamper blade assembly is connectedto a cast zinc shaft supported by self-lubricating bearings. The shaft is castwith a damper position indicator. Thevalve assembly includes a mechanicalstop to prevent over-stroking. At 4 in.wg, air valve leakage does not exceed1% of cataloged airflow.
FAN MOTORSingle-speed, direct-drive, permanentsplit capacitor type. Thermal overloadprotection provided. Motors will bedesigned specifically for use with anopen SCR. Motors will accommodateanti-backward rotation at start up.Motor and fan assembly are isolatedfrom terminal unit.
FAN SPEED CONTROL
Variable Speed Control Switch(SCR)—The SCR speed control deviceis provided as standard and allows theoperator infinite fan speed adjustmentso the fan output may be modified toachieve exact cfm requirements.
Air Valve/Fan Combinations Available:
Air Valve FanSize Airflow Airflow(in.) (cfm) Size (cfm)
06 500 01 50002 615
08 900 01 50002 61503 92504 1150
10 1400 02 61503 92504 115005 1675
12 2000 03 92504 115005 167506 2350
14 3000 05 167506 235007 2500
16 4000 06 235007 2500
Air Valve FanSize Airflow Fan Airflow
(mm) (L/s) Size (L/s)
06 (152) 236 01 23602 290
08 (203) 425 01 23602 29003 43704 543
10 (254) 661 02 29003 43704 54305 791
12 (305) 944 03 43704 54305 79106 1109
14 (356) 1416 05 79106 110907 1180
16 (406) 1888 06 110907 1180
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MechanicalSpecifications
TRANSFORMERThe 50-VA transformer is factory-installed in the fan control box toprovide 24 VAC for controls.
POWER DISCONNECTThe power disconnect is provided asstandard and allows the operator toturn the unit on or off by toggling tothe appropriate setting. This switchbreaks both legs of power to the fanand the electronic controls (ifapplicable)
OUTLET CONNECTION
Flanged Connection—A rectangularopening on the unit discharge toaccept a 90° flanged ductworkconnection.
FILTERA 1" (25 mm) filter is provided on theplenum inlet and attaches to the unitwith a filter frame.
ACCESS PANELInternal access to unit is achievedthrough plenum inlet for cooling andelectric units. For hot water units, thepanel opposite of control side slidesopen for access.
HOT WATER COIL
Parallel Water Coils—factory-installed on the plenum inlet.
The coil has 1-row with 144 aluminum-plated fins per foot (.305 m), and ifneeded 2-row with 144 aluminum-plated fins per foot (.305 m). Full fincollars provided for accurate finspacing and maximum fin-tubecontact. The 3/8" (9.5 mm) ODseamless copper tubes aremechanically expanded into the fincollars. Coils are proof tested at 450psig (3102 kPa) and leak tested at 300psig (2068 kPa) air pressure underwater. Coil connections are brazed withright-hand configuration.
ELECTRIC HEAT COILThe electric heater is factory-providedand installed, UL recognized resistanceopen-type heater. It also contains adisc-type automatic pilot duty thermalprimary cutout, and manual reset loadcarrying thermal secondary device.Heater element material is nickel-chromium. The heater terminal box isprovided with 7/8" (22 mm) knockoutsfor customer power supply. Terminalconnections are plated steel withceramic insulators. Heater control
access is on the discharge side ofthe unit.
ELECTRIC HEAT OPTIONS
ContactorsMagnetic Contactor—An electricheater 24-volt contactor for use withdirect digital control (DDC) or analog-electronic controls.
Mercury Contactor—An electricheater 24-volt contactor for use withdirect digital control (DDC) or analog-electronic controls.
P.E. Switch with MagneticContactor—This switch andmagnetic contactor is for use withpneumatic controls.
P.E. Switch with MercuryContactor—This switch andmercury contactor is for use withpneumatic controls.
Airflow Switch—An air pressuredevice designed to disable the heaterwhen the system fan is off.
Power Fuse—If power fuse is chosenwith a unit with electric heat, then asafety fuse located in the electricheater’s line of power to prevent powersurge damage to the electric heater.
Any electric heat unit with a calculatedMCA greater than or equal to 30 willhave a fuse provided.
Disconnect Switch—A factory-provided door interlockingdisconnect switch on the heater controlpanel disengages primary voltage tothe terminal.
UNIT CONTROLS SEQUENCE OFOPERATIONThe unit controller continuouslymonitors the zone temperature againstits setpoint and varies the primaryairflow as required to meet zonesetpoints. Airflow is limited byminimum and maximum position setpoints. For a parallel unit, the controllerwill intermittently start the fan upon acall for heat. Upon a further call forheat, any hot water or electric heatassociated with the unit is enabled.
1. Primary Airflow—The fan energizeswhen primary airflow drops belowthe fan setpoint airflow. The fanautomatically starts when the zonetemperature drops to the heatingtemperature setpoint.
2. Zone Temperature—The fanenergizes when the zone temperaturedrops to a selectable number ofdegrees above the heatingtemperature setpoint.
DIRECT DIGITAL CONTROLS
DDC Actuator—Trane 3-wire, 24-VAC,floating-point control actuator withlinkage release button. Torque is35 in-lb minimum and is non-springreturn with a 90-second drive time.Travel is terminated by end stops atfully-opened and -closed positions. Anintegral magnetic clutch eliminatesmotor stall.
Direct Digital Controller—Themicroprocessor-based terminal unitcontroller provides accurate, pressure-independent control through the useof a proportional integral controlalgorithm and direct digital controltechnology. The controller, named theUnit Control Module (UCM), monitorszone temperature setpoints, zonetemperature and its rate of change,and valve airflow using a differentialpressure signal from the pressuretransducer. Additionally, the controllercan monitor either supply duct airtemperature or CO2 concentration viaappropriate sensors. The controller isprovided in an enclosure with 7/8"(22 mm) knockouts for remote controlwiring. A Trane UCM zone sensoris required.
DDC Zone Sensor—The UCMcontroller senses zone temperaturethrough a sensing element located inthe zone sensor. In addition to thesensing element, zone sensor optionsmay include an externally-adjustablesetpoint, communications jack for usewith a portable edit device, and anoverride button to change theindividual controller from unoccupiedto occupied mode. The override buttonhas a cancel feature that will return thesystem to unoccupied. Wired zonesensors utilize a thermistor to vary thevoltage output in response to changesin the zone temperature. Wiring to theUCM controller must be 18- to 22-awg.twisted pair wiring. The setpointadjustment range is 50–88ºF (10–31°C).Depending upon the features availablein the model of sensor selected, thezone sensor may require from a 2-wireto a 5-wire connection. Wireless zonesensors report the same zoneinformation as wired zone sensors,but do so using radio transmittertechnology. Therefore with wireless,wiring from the zone sensor to theUCM is unnecessary.
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MechanicalSpecifications
Digital Display Zone Sensor withLiquid Crystal Display (LCD)—The digital display zone sensor containsa sensing element, which sends a signalto the UCM. A Liquid Crystal Display(LCD) displays setpoint or spacetemperature. Sensor buttons allow theuser to adjust setpoints, and allow spacetemperature readings to be turned on oroff. The digital display zone sensor alsoincludes a communication jack for usewith a portable edit device, and anoverride button to change the UCM fromunoccupied to occupied. The overridebutton has a cancel feature, whichreturns the system to unoccupied mode.
The digital display zone sensor requiresseven wires.
System Communications—TheController is designed to send andreceive data from a Tracer Summit® orother Trane controllers. Current unitstatus conditions and setpoints may bemonitored and/or edited via this datacommunication feature. The networktype is a twisted wire pair shieldedserial communication.
ANALOG ELECTRONIC CONTROLSAnalog Actuator—A Trane 3-wire,24-VAC, floating-point control actuatorwith linkage release button. Torque is35 in-lb minimum and is non-springreturn with a 90-second drive time.Travel is terminated by end stops atfully-opened and -closed positions. Anintegral magnetic clutch eliminatesmotor stall.
Analog Electronic Controller—The controller consists of a circuitboard that offers basic VAV unitoperation and additional overridefunctions and operates using 24 VACpower. The controller uses a capacitivetype pressure transducer to maintainconsistent air delivery regardless ofsystem pressure changes. The enclosurehas 7/8" (22 mm) knockouts for remotecontrol wiring. A Trane electronic zonesensor is required.
Analog Electronic Thermostat—This single-temperature, wall-mountedelectronic device utilizes a thermistorto vary the voltage output in responseto changes in the zone temperature.Connections to the VAV unit circuitboard are made using standard three-conductor thermostat wire. The setpointadjustment range is 63–85ºF (17–29°C).The sensor is available in two models.One model has a concealed, internally-adjustable setpoint. The other modelhas an externally-adjustable setpoint.
PNEUMATIC CONTROLS
Normally Open Actuator –Pneumatic 3 to 8 psig (20 to 55 kPa)spring-range pneumatic actuator.
3011 Pneumatic Volume Regulator(PVR) – The regulator is a thermostatreset velocity controller, whichprovides consistent air delivery within5% of cataloged flow down to 18% ofunit cataloged cfm, independent ofchanges in system static pressure.Factory-calibrated, field-adjustablesetpoints for minimum and maximumflows. Average total unit bleed rate,excluding thermostat, is 28.8 scim at20 psig (7.87 ml/min at 138 kPa) supply.
UNIT OPTIONS
Power Fuse (VPCF, VPWF)—Optional fuse is factory-installed in theprimary voltage hot leg.
HOT WATER VALVES
Two-Position Valve—The valve is afield-adaptable, 2-way or 3-wayconfiguration and ships with a cap tobe field-installed when configured as a2-way valve. All connections areNational Pipe Thread (NPT). The valvebody is forged brass with a stainlesssteel stem and spring. Upon demand,the motor strokes the valve. When theactuator drive stops, a spring returnsthe valve to its fail-safe position.
Electrical Rating – 7 VA at 24 VAC,6.5 Watts, 50/60 Hz
8 feet (2.44 m) of plenum rated wirelead is provided with each valve.
Proportional Water Valve – The valveis a field-adaptable, 2-way or 3-wayconfiguration and ships with a cap overthe bottom port. This configures thevalve for 2-way operation. For 3-wayoperation, remove the cap. The valve isdesigned with an equal percentageplug. The intended fluid is water orwater and glycol (50% maximumglycol). The actuator is a synchronousmotor drive. The valve is driven to apredetermined position by the UCMcontroller using a proportional plusintegral control algorithm. If power isremoved, the valve stays in its lastposition. The actuator is rated forplenum applications under UL 94-5Vand UL 873 standards.
Pressure and Temperature Ratings –The valve is designed and tested in fullcompliance with ANSI B16.15 Class250 pressure/temperature ratings,ANSI B16.104 Class IV control shutoffleakage, and ISA S75.11 flowcharacteristic standards.
Flow Capacity – 7.30 Cv, 4.60 Cv, 1.80Cv, 0.79 Cv
Overall Diameter – ½" NPT, ¾" NPT(7.3 Cv)
Maximum Allowable Pressure – 345 psi(2415 kPa)
Maximum Operating FluidTemperature – 281ºF (138°C)
Maximum Close-off Pressure – 55 psi(379 kPa)
Electrical Rating – 4 VA at 24 VAC.
10 feet (3.05 m) of plenum rated22-gage wire for connection.Terminations are #6 stabs.