Cga Svx01b en 0404 Trane

8/4/2019 Cga Svx01b en 0404 Trane

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CGA-SVX01B-EN

Air-Cooled Water Chiller

Air-Cooled Water Chillerwith Heat Pump Option

3~30 Tons

InstallationOperationMaintenance


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American Standard Inc. 2004 CGA-SVX01B-EN2

TABLE OF CONTENTS

MODEL NOMENCLATURE

INSTALLATIONRIGGINGMOUNTINGWATER PIPING

FIGURE 1 : RECOMMENDED HOISTING ARRANGEMENTFIGURE 2 : DIMENSION FOR MOUNTING

FIGURE 3 : SERVICE & MAINTENANCE CLEARANCEELECTRICAL WIRINGUNIT POWER SUPPLY

FIGURE 4 : TYPICAL PIPING ARRANGEMENTFIGURE 5 : TYPICAL SYSTEM APPLICATION

ELECTRICAL DATA

FLOW SWITCH INTERLOCKCIRCUIT DIAGRAM 1 : FOR CGAK 030~075CIRCUIT DIAGRAM 2 : FOR CGAR 030~075CIRCUIT DIAGRAM 3 : FOR CGAK 100~200CIRCUIT DIAGRAM 4 : FOR CGAR 100~200CIRCUIT DIAGRAM 5 : FOR CGAK 250~300

INSTALLATION CHECKLIST

PRE-START PROCEDUREVOLTAGE UTILIZATION RANGEVOLTAGE IMBALANCEWATER FLOW RATEUNIT WATER PRESSURE DROP

FIGURE 6 : HYDRAULIC CHARACTERISTICPRE-START CHECKLIST

OPERATIONSTART-UP PROCEDUREEXTENDED UNIT SHUT-DOWN/WINTERIZATIONSTANDARD AMBIENT OPERATIONOPTIONAL LOW AMBIENT OPERATION (CGAK)OPTIONAL HEAT PUMP OPERATION (CGAR)ELECTRICAL CONTROL & PROTECTION SYSTEM

MAINTENANCE

TROUBLE ANALYSIS

3

4

11

12

18

23

27

28


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MODEL NOMENCLATURE

CGA1,2,3

K4

0505,6,7

58

D9

F10

R11

M12

R13

N14

A15

DIGIT 1,2,3CGA=Air-Cooled Water Chiller

DIGIT 4 - ModelK=Cooling Only

R=Cooling With Heat Pump Option

DIGIT 5,6,7 - Nominal Capacity (tons)030040050075100125150175200

250300

DIGIT 8 - Voltage1=220V/60Hz/1Ph

(For model 030,040,050)2=220V/60Hz/3Ph

(For model 050,075,100,125,150,175,200,250,300)3=380V/60Hz/3Ph

(For model 050,075,100,125,150,175,200,250,300)4=460V/60Hz/3Ph

(For model 050,075,100,125,150,175,200,250,300)5=380V/50Hz/3Ph

(For model 050,075,100,125,150,175,200,250,300)6=400V/50Hz/3Ph

(For model 050,075,100,125,150,175,200,250,300)7=415V/50Hz/3Ph

(For model 050,075,100,125,150,175,200,250,300)

DIGIT 9 - Development SequenceD=Fourth Design

DIGIT 10 - ControlsF=Fixed Entering Water Temperature Control

(Standard Option)A=Microprocessor Controller

(Adjustable Entering Water Temperature) (For CGAK Models as Optional) (For CGAR Models as Standard Option)

DIGIT 11- Water PumpN = No PumpR = Standard Pump

(Standard Option)

DIGIT 12 - Refrigerant Pressure Gauges

M = No (Standard Option)

G = With High/Low Pressure Gauges

DIGIT 13 - Temperature KitR = Standard Ambient Temperature Kit

(Standard Option)L = Low Ambient Temperature Kit

(For CGAK Models Only)

DIGIT 14 - Other OptionsM = Standard Fin + Standard Grille CoverC = Blue Fin + Standard Grille Cover

DIGIT 15 - Service SequenceA = First


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American Standard Inc. 2004 4 CGA-SVX01B-EN

INSTALLATION

Complete the Installation Checklist duringinstallation to verify completion of allrecommended procedures before unitstart-up.

RIGGINGEach unit is bolted to a shipping skid forshipment to the job site. Move the unit using

a forklift of suitable capacity. See Table 1 forunit shipping weights.

Locate the unit near a large-capacity drain toallow system drainage during unit shutdownand repair. Rig the unit using canvas belt.Fasten the belt to the unit over the unitsbase as show in Figure 1.

MOUNTINGMounting methods that will minimize soundand vibration problems are:

1. Mount the unit directly on an isolatedconcrete pad or on isolated concretefootings at each unit mounting point.

2. Install the optional neoprene or spring

isolators at each mounting location.

Refer to Figure 2 for unit and basedimensions and Figure 3 for recommendedservice clearance.

WATER PIPINGThoroughly flush all water system pipingbefore making the final piping connections tothe unit.

Table 1 : Unit Shipping Weights

Maximum Shipping Weight (Kg)

230

250

260

320

370

450

530

550

570

750

800

Model

030

040

050

075

100

125

150

175

200

250

300


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American Standard Inc. 2004 6

Figure 2 :Dimension for Mounting(CGAK-075 As Shown)Note: All Dimensions in Millimeter

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7

Figure 3 :Service and Maintenance Clearance(CGAK-075 As Shown)

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CAUTION: If using an acidic commercial flushing solution, construct a temporary bypass around the unit to prevent damage to the evaporator.

CAUTION: To avoid possible equipment damage, do not use untreated or improperly treated water.

For units water connection sizes andlocations, please refer to Figure 2.

CAUTION: To prevent unit damage, do not reverse system piping connections to the unit; water entering the unit must enter at the designated Water In and leaving water must exit the unit through the designated Water Out connection.

Figure 4 illustrates typical unit pipingcomponents. Components and layout willvary slightly depending upon the locationsof the connections and water source.

Figure 5 gives a schematic of a typicalsystem application for this unit.

Provide vents at high points in the piping tobleed air from the chilled water system.Install pressures gage(s) to monitor enteringand leaving chilled water pressure.

CAUTION: To prevent damage to the waterside components of unit, do not allow evaporator pressure to exceed 100 psig (i.e. maximum working pressure).Use an expansion tank to isolate this pressure if water pressure exceeds this value.

ELECTRICAL WIRING

WARNING: To prevent injury or death,disconnect electrical power source before completing wiring connections to the unit.

CAUTION: Use only copper conductors for terminal connections to avoid

corrosion or over heating.Figure 2 shows the location of the unitelectrical access openings. Table 2 providesminimum circuit ampacities, recommendedfuse sizes, and motor electrical data.

UNIT POWER SUPPLYRefer to the unit wiring schematic fixed tothe control panel cover. The installer mustprovide a power supply of proper voltageand a fused disconnect switch to the unit.

Run properly sized power wirings throughthe electrical access opening on the side ofthe unit, and connect it to the VoltageTerminal Block (1TB1) in the unit controlpanel. Install a fused disconnect switch asrequired by local codes. Provide properequipment grounds for the groundconnections in the unit control panel and atthe fused disconnect switch.

Refer to wiring diagrams from Page 12 toPage 16 for reference of a typical unit

installation. For actual wiring diagram, referto the one fixed to the control panel cover.

FLOW SWITCH INTERLOCKTo avoid possible evaporator freeze-upresulting from reduced water flow, install aflow switch ( or other flow sensing device) inthe evaporator outlet water line. Thissensing device must be adjusted to stopcompressor operation if water flow to theevaporator drops below 70% of the system

design full-flow rate.The installer must provide interconnectingwiring between the unit control panel andthe water flow sensing switch in theevaporator water line.


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Figure 4 :Typical Piping Arrangement(CGAK-075 As Shown)

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Figure 5 :Typical System Application(CGAK-075 And Fans As Shown)

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11

Table 2 : Electrical Data60Hz

ElectricalPower

(V/Hz/Ph)220/60/1220/60/1220/60/1220/60/1

220/60/3380/60/3220/60/3380/60/3220/60/3380/60/3220/60/3380/60/3220/60/3380/60/3220/60/3380/60/3220/60/3380/60/3220/60/3380/60/3220/60/3380/60/3

ModelWaterPumpFLA4.44.44.46.5

2.71.64.22.44.22.45.43.15.43.16.03.59.15.39.15.3

11.36.5

Comp1

RLA14.419.424.424.4

15.38.823.013.315.38.817.410.123.013.226.015.032.418.735.020.051.029.0

Comp2

RLA---

24.4

----

15.38.8

17.410.123.013.226.015.032.418.751.029.051.029.0

Fan1

FLA2.82.82.84.3

3.01.73.01.74.52.64.52.63.01.74.52.64.52.64.52.64.52.6

Fan2

FLA----

--------

3.01.74.52.64.52.64.52.64.52.6

UnitMCA

25.231.537.765.7

24.814.336.020.743.124.849.128.463.236.273.542.591.052.6

116.966.8

135.177.0

Rec.FuseSize28.836.343.871.8

28.716.541.724.147.027.053.431.068.939.580.046.299.157.3129.674.0147.884.2

MaxFuseSize39.650.962.190.1

40.123.159.034.058.433.666.538.586.249.499.557.5

123.471.3

167.995.8

186.1106.0

030040050100

050050075075100100125125150150175175200200250250300300

50Hz

ElectricalPower

(V/Hz/Ph)380-415/50/3380-415/50/3380-415/50/3

380-415/50/3380-415/50/3380-415/50/3380-415/50/3380-415/50/3380-415/50/3

ModelWaterPumpFLA1.11.41.4

1.71.72.02.82.85.9

Comp1

RLA7.411.67.4

8.711.613.015.115.025.0

Comp2

RLA--

7.4

8.711.613.015.125.025.0

Fan1

FLA1.51.52.2

2.21.52.22.22.22.2

Fan2

FLA---

-1.52.22.22.22.2

UnitMCA

11.917.420.3

23.530.836.541.253.566.6

Rec.FuseSize13.720.322.1

25.733.739.845.059.772.8

MaxFuseSize19.329.027.7

32.242.449.556.378.591.6

050075100

125150175200250300

Note: All voltages supply must fall within the utilization range of 10 % Minimum Circuit Ampacity (MCA) = Largest Load x 1.25 + Sum of additional Loads. (Used for sizing wire) Recommended Fuse Size (REC) = Largest Load x 1.5 + Sum of additional Loads. (Select closest fuse size) Maximum Fuse Size (MFS) = Largest Load x 2.25 + Sum of additional Loads. (Select equal or next lower fuse size)

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ELECTRICAL DATA


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Circuit Diagram 1 :For CGAK 030~075

FLOW SWITCH INTERLOCK

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Circuit Diagram 2 :For CGAR 030~075

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Circuit Diagram 3 :For CGAK 100~200

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Circuit Diagram 4 :For CGAR 100~200

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17 CGA-SVX01B-EN

INSTALLATION CHECKLISTRECEIVING

Verify that unit nameplate datacorresponds with sales order information.Inspect unit for shipping damages andmaterial shortages; report any damagesor shortages found to the carrier.

UNIT LOCATION AND MOUNTINGInspect unit installation location foradequate ventilation.Provide drainage facilities for wateraccumulated from the base.Remove and discard any shippingmaterials (e.g. cartons, crates, etc.)Inspect to determine that service accessclearances are adequate.Install optional unit neoprene-in-shear orspring isolators.Secure unit to mounting surface.Level the unit.

EVAPORATOR PIPINGFlush and clean all chilled water piping.

CAUTION: If using an acidic commercial flushing solution, construct a temporary bypass around the unit to prevent damage to the evaporator.

CAUTION: To avoid possible equipment damage, do not use untreated or improperly treated water.

Make evaporator water connections.Vent the air from chilled water system athigh points.Install pressure gauges, thermometersand shutoff valves on water inlet andoutlet piping.Install water strainer in evaporator supplyline.Install balancing valve and flow switch onwater outlet piping.

ELECTRICAL WIRING

CAUTION: Use only copper conductors to prevent galvanic corrosion and overheating at terminal connections.

Connect unit power supply wiring (withfused disconnect) to appropriateterminals on terminal block (TB) in powersection of unit control panel.In order to turn on/off the chiller fromindoors, connect wiring across reservedterminals 2 & 3 in the unit control panelfrom an indoor REMOTE OFF/ON switch.Properly ground the unit, the chilled waterpump motor, all disconnects, and otherdevices which require grounds.Install wiring to connect flow switch to unitcontrol panel.

FOR NO-PUMP OPTION ONLYConnect chilled water pump power supply

wiring (with fused disconnect) to theproper terminals of the chilled waterpump.Install wiring to connect chilled waterpump switch to chilled water pumpstarter.Connect auxiliary contacts of chilledwater pump starter to flow switch and unitcontrol panel.


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PRE-START PROCEDURES

VOLTAGE UTILIZATIONRANGEElectrical power to the unit must meetstringent requirements for unit to operateproperly. Total voltage supply and voltageimbalance between phases should be withinthe following tolerances.

Measure each leg supply voltage at all linevoltage disconnect switches. Readings mustfall within the voltage utilization range shownon the unit nameplate ( 10%). If voltage onany leg does not fall within the tolerance,notify the power company to correct thissituation before operating the unit.Inadequate voltage to the unit will causecontrol components to malfunction andshorten the life of electrical components andcompressor motors.

VOLTAGE IMBALANCEExcessive voltage imbalance betweenphases in all 3-phase system will causemotors to overheat and eventually fail.Maximum allowable imbalance is 2 %.Voltage imbalance is defined as follows:

The 2.2% imbalance that exists in theexample above exceeds maximumallowable imbalance by 0.2 %. This muchimbalance between phases can equal asmuch as 20 % current imbalance with aresulting increase in winding temperaturethat will decrease compressor motor life.

WATER FLOW RATEEstablish a balanced water flow through theunit. Flow rates should fall between theminimum and maximum values indicated inTABLE 3. Evaporator water flow rates belowthe minimum acceptable values will result ina stratified flow; this reduces heat transferand causes either loss of expansion valvecontrol or repeated nuisance low pressurecutouts. Conversely, excessively high flowrate may cause erosion in the water system.

% Voltage Imbalance =

WhereVa = (V1 + V2 +V3) / 3(Average Voltage)V1, V2, V3 = Line VoltagesVd = Maximum Line Voltage deviation from Va

Example:If the three voltages measured at the line 221Volts, 230 Volts, and 227 Volts, the average(Va) would be:Va = (221 + 230 + 227)/3 = 226 Voltsthen Vd = 221 VoltsThe percentage of imbalance is then:

100x Va-VdVa

100x 226-221226

2.2%


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Table 3 : Unit Water Flow Rate60Hz

Model

030

040

050

075

100

125

150

175

200

250

300

Minimum Flow

18.5

22.9

30.2

44.9

59.1

74.7

89.5

102.6

120.0

147.3

175.3

Rated Flow

27.7

34.3

45.3

67.3

88.7

112.0

134.3

154.0

180.0

221.0

263.0

Maximum Flow

38.8

48.0

63.4

94.2

124.2

150.0

150.0

175.0

240.0

290.0

350.0

Units: LPMUNIT WATER PRESSUREDROPMeasure the water pressure rise across thestandard unit (with built-in pump). TheExternally Available Head (E.A.H) shouldapproximate those indicated by the E.A.H.curves, with the corresponding flow rates.For units (without built-in pump) with field-

installed pump outside the unit, waterpressure drop across the unit shouldapproximate those indicated by the InternalPressure Loss (I.P.L.) curves, with thecorresponding flow rates.

For standard unit with built-in pump, refer tothe E.A.H. curve for the system hydraulicdesign. For optional unit without a built-inpump, refer to the I.P.L. curves. (Refer toFigure 6 for hydraulic characteristics of allmodels.)

Model

050

075

100

125

150

175

200

250

300

Minimum Flow

25.1

37.3

49.1

62.1

74.4

85.5

98.3

124.6

148.6

Rated Flow

37.7

56.0

73.7

93.3

111.7

128.3

149.0

187.0

223.0

Maximum Flow

56.6

84.0

110.6

140.0

150.0

160.0

190.0

240.0

300.0

Units: LPM50Hz

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Figure 6 :Hydraulic Characteristics - 60Hz

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50Hz

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23 CGA-SVX01B-EN

OPERATION

START-UP PROCEDUREClose the fused disconnect switch andturn REMOTE/OFF/ON switch to ON.Pump will start immediately. After 2minutes, compressors 1 will start. 1minute later, compressor 2 will start(only in units with two refrigerant circuits).

For CGAR models, turn REMOTE/OFF/

ON switch to ON as described above,turn the already installed indoors coolingand heating mode switch to coolingmode, then the operation of the chillerwould be similar to what is describedabove. As for start-up with heating mode,first turn REMOTE/OFF/ON switch toOFF. Then, turn the cooling and heatingmode switch to heating. Finally, turn theREMOTE/OFF/ON switch to ON (seesection on electrical wiring of theinstallation checklist).

Once the unit has operated for at least 30minutes and the system has stabilized,complete the following checklist to ensureproper unit operation.

Re-check unit water flow and pressurerise (for no built-in pump unit with field-installed pump system). These readingsshould be stable at proper levels.Measure unit suction and dischargepressures by installing pressure gaugeson the discharge and suction line accessports. Normal operation should render

suction pressure in the range of 50-85psig and discharge pressure 200-310psig.

Check compressor amp draw.Check electrical power supply.Check the liquid line sight glasses.

NOTE: Bubbles in the liquid line may indicate either a low refrigerant charge,or excessive pressure drop in the liquid line. Such a restriction can often be identified by a noticeable difference in

line temperature on either side of the restricted area. (Frost often forms on the outside of the liquid line at the point of restriction, as well). Bubbles are not necessarily a symptom of improper system operation.

CAUTION: A clear sight glass does not necessarily mean that the system is sufficiently charged; be sure to consider system superheat, subcooling, and unit operating pressures and ambient temperatures.

Proper unit refrigerant charge-per circuit-isindicated on the unit nameplate.

Measure system superheat.

Normal system superheat is 6.7 C to 8.3Cfor each circuit at ARI conditions (12.2Centering water, 6.7 C leaving water, and35C ambient temperature). If the superheatmeasured for either circuit does not fallwithin this range, alter the setting of thesuperheat adjustment on the thermalexpansion valve to obtain the desired

reading. Allow 15 to 30 minutes betweenadjustments for the expansion valve tostabilize at each new setting.

Measure system subcooling.

Normal subcooling for each circuit is 6.7Cto 12.2C ARI conditions (12.2C enteringwater, 6.7 C leaving water, and 35 Cambient temperature). If subcooling foreither circuit is normal but subcooling is notin this range, check superheat for the circuitand adjust, if required. If superheat is normal

but subcooling is not, contact a qualifiedservice technician.

If operating pressure, sight glass,superheat and subcooling readingsindicate refrigerant shortage, find andrepair leaks and, gas-charge refrigerantinto each circuit. Refrigerant shortage isindicated if operating pressures are lowand subcooling is also low.

CAUTION: If suction and discharge pressures are low, but subcooling is normal, no refrigerant shortage exists.Adding refrigerant will result in overcharging.

Add refrigerant vapor with the unit runningby charging through the access port on thesuction line until operating pressures arenormal.

If operating pressures indicate anovercharge, slowly (to minimize oil loss)recover refrigerant at the liquid lineservice valve.Be sure that all remote sensing bulbs are

properly installed in bulb wells with heattransfer grease. Remote bulb capillarytubes must be secured (i.e. protectedfrom vibration and abrasion) andundamaged.Inspect the unit. Remove any debris,tools and hardware. Secure all exteriorpanels, including the control andcompressor access panels. Replace andtighten all retaining screws.


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EXTENDED UNIT SHUT-DOWN/WINTERIZATIONIf the system is taken out of operation forlong periods of time for any reasons (e.g.,seasonal shutdown), use this procedure toprepare the system for shutdown.

1. Check the refrigerant piping for leaks,

fixing any that exist.2. Service the chilled water pump and anyair handling equipment according to themanufacturer s recommendtions.

3. Open both electrical disconnect switchesfor the unit and chilled water pump; lockboth disconnects in the open position.

WINTERIZATION: Close all evaporator water supply valves and drain the evaporator by removing the drain plug and opening the vent on the entering water line just outside the unit. Re-install the drain plug. Since the evaporator does not drain completely, add ethylene glycol antifreeze to the remaining water through the vent or evaporator drain hole, to keep the water from freezing. Protect system to 5.5 C below the expected ambient temperature.

SYSTEM RESTART AFTER EXTENDEDSHUTDOWN1. Remove winterization antifreeze as it can

reduce system capacity.

2. Fill the chilled water circuit by opening thegate valves at the returning and supplywater piping. Be sure to vent the systemwhile filling it, and close the vents whensystem is full.

3. Remove compressor delay on timer(s)(TR1, TR2). Record down the originalsocket for the respective timer so that thecorrect timer(s) are replaced correctlylater.

4. Close the unit disconnect switch for powersupply.

5. Turn the REMOTE/OFF/ON switch to ONposition. With water circulating throughthe chilled water system, inspect allpiping connections for leaks and makeany necessary repairs.

6. Adjust the water flow rate, using thebalancing valve, through the chilled watercircuit, and check the water pressure rise(or drop) through the unit.

7. Adjust the flow switch (installed on theunit outlet piping) to provide properoperation.

NOTE: With the unit operating, throttle

the water flow to approximately 50% of the full flow rate. Following the manufacturers instructions, adjust the flow switch contacts to open at this point. Use an ohmmeter to check for contact opening and closure.

8. Stop the unit by turning the REMOTE/ OFF/ON switch to OFF position.

9. Replace compressor delay on timer (TR1,TR2) back to their original sockets.

This unit now is ready for normal operation.

STANDARD AMBIENTOPERATIONStandard unit will operate in outdoor ambienttemperature down to 15 C.

OPTIONAL LOW AMBIENTOPERATION (CGAK)

A factory installed Low Ambient Unit (LAU)option will enable units to operate at outdoorlow ambient temperature (see Table 4).

OPTIONAL HEAT PUMPOPERATION (CGAR)A factory installed heat pump unit (CGAR)option will enable units to get either coolingand heating performance (not simultaneous).When the unit is switched to heating mode,the four-valve is activated. Evaporator

becomes the condenser while the condenserbecomes the evaporator. There are twoliquid lines in a CGAR unit. One is for coolingmode while another is for heating mode.

To carefully measure the high pressure,there are two access ports in these twoliquid lines. If you operate this unit in coolingmode, connect high pressure gauge to theaccess port of the cooling liquid line. Whileoperating this unit in heating mode, mustchange the connection to the access port ofthe heating liquid line.

A timer override low pressure switch delaysfor 2 minutes to prevent nuisance trip-outs.


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25 CGA-SVX01B-EN

ELECTRICAL CONTROL &PROTECTION SYSTEM

Low Pressure Cutouts (LP1, LP2)These units are protected by low pressurecutouts that open and stop compressoroperation if the operating pressure dropsbelow 25 4 psig . The cutout automaticallyresets when the pressure reaches 50 4psig. The LP is a SPDT device and if itopens at low ambient start-up, there will bea 2 minute override to prevent nuisancetrip-outs ( for LAU only).

High Pressure Cutouts (HP1, HP2)These units have high pressure cutouts thatopen and stop compressor operation if thedischarge pressure reaches 400 7 psig.The cutout automatically resets whenpressure drops to 300 20 psig.

Reset Relays (CR1,CR2)

If the unit is shut down by safety devices(LP, HP, FS, FU, KF etc.) the reset relaylocks out the compressor contactor (MC1,MC2). This prevents the system fromrecycling until the condition that caused thesafety devices to trip is determined andcorrected.

CAUTION: To prevent unit damage, do not reset the control circuit until the cause of the safety lockout is identified and corrected.

To reset CR1 and CR2, open and reclosethe unit REMOTE/OFF/ON switch.

Anti-freeze Cutout (FS1, FS2, FU)The FS and FU are designed to protect theevaporator from freeze damage in the eventof a water temperature thermostat (WTT)malfunction or restricted water flow. TheFUs remote sensing bulb is mounted at theoutlet end of the evaporator, where itmonitors leaving water temperature. If

during normal unit operation, the leavingchilled water temperature falls to the trippoint, the FU will open to interrupt compres-sor operation.

When leaving chilled water temperature fallsdown, the suction temperature also fallsdown. For further protection to avoid freezedamage, another freezestat ( FS1 , FS2 ) in

contact with the suction line. If suctiontemperature falls to the trip point , the FS1(FS2) will open to interrupt compressoroperation.

Motor OverloadsThese units have internal compressor andcondenser fan motor overloads to protectthe motors from overcurrent and overheat-ing conditions and automatically reset assoon as they cool sufficiently. Pump motorhas thermal overload installed at the loadcontactor. Pump overload needs manual

reset.Cooling ModeWater Temperature ThermostatOperation (TS1, TS2) for cooling mode

For Double Refrigeration Circuit OperationAt Start-up, the pump will come onimmediately. Two minutes after the pump ison and EWT(entering water temperature)isabove 14.0 C, compressor 1 will start.One minute later, if the EWT is above 13.5C, compressor 2 will start.

When cooling demand is met and EWTdrops to 10.0 C. Compressor 1 will stop,ifEWT continues to fall to 9.5 C,compressor

2 will stop. Subsequently,when loadbuilds up and EWT rises to 13.5 C com-pressor 2 comes on, and if EWT risesfurther to 14.0C, compressor 1 comes on.Pump remains on unless the unit is turnedoff.

For Single Refrigeration Circuit OperationFor units with only one refrigerant circuit, theoperation of water pump, fan and compres-sor is exactly the same. The only differenceis the unit will operate the single compressorfrom any temperature over 14.0 C and 10.0C when the compressor will stop.

Heating Mode

Water Temperature ThermostatOperation (TS3, TS4) for cooling mode

For Double Refrigeration Circuit OperationAt start-up, pump will come on immediately.Two minutes after the pump is on and EWT(entering water temperature)is below 38.0C, compressor 1 will start. One minutelater, if EWT is below 39.0 C, compressor2 will start.

When heating demand is met and EWTrises to 42.0 C, compressor 1 will stop, ifEWT continues to rise to 43.0 C,compres-sor 2 will stop. Subsequently,when loadbuilds up and EWT drops to 39.0 C,compressor 2 comes on, and if EWTdrops further to 38.0 C, compressor 1comes on. Pump remains on unless the unitis turned off.

For Single Refrigeration Circuit OperationFor units with only one refrigerant circuit, theoperation of water pump, fan and compres-sor is exactly the same. The only differenceis the unit will operate the single compressorfrom any temperature below 38.0 C and 42.0 C when the compressor will stop.


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29 CGA-SVX01B-EN

C. 2nd Stage Compressor Fails To Start

Probable Cause(1) Time delay contacts fail to close(2) No call for cooling

(3) Unit locked out by reset relay (CR)(4) Compressor contactor will not close

Recommended ActionReplace time delay relayCheck for the followings:a. Defective thermostatb. Broken or improper control windingSee (A) item (4)See (A) item (5)

D. Compressor Short Cycles

Probable Cause(1) Intermittent contact in control circuit

Recommended ActionCheck for the followings:a. Defective relay contactsb. Loose wiring connections

E. Compressor Runs Continuously

Probable Cause(1) Unit undersized for load (cannot maintain water temperature)(2) Thermostat setpoint too low(3) Defective thermostat or control wiring

(4) Welded contacts on compressor contactor(5) Leaky valves in compressor (indicated by abnormally low

discharge and high suction pressures)(6) Shortage of refrigerant (indicated by reduced capacity, high

superheat, low subcooling, and low suction pressure)

Recommended ActionCheck for cause of excessive loadReadjust thermostatReplace thermostatReplace or repair control wiringRepair or replace contactorReplace compressor

Find and repair refrigerant leakRecharge system

F. Compressor Motor Winding Stat Open

Probable Cause(1) Excessive load on evaporator (indicated by high supply water

temperature)

(2) Lack of motor cooling (indicated by excessive superheat)

(3) Improper voltage at compressor

(4) Internal parts of compressor damaged

Recommended ActionCheck for the followings:a. Excessive water flow

b. High return water temperatureCheck for the followings:a. Improper expansion valve settingb. Faulty expansion valvec. Restriction in liquid lineCheck for the followings:a. Low or imbalanced line voltageb. Loose power wiringc. Defective compressor contactorReplace compressor


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G. Compressor is Noisy

Probable Cause(1) Internal parts of compressor damaged or broken (compressor

knocks)(2) Liquid floodback (indicated by abnormally cold suction line and

low superheat)(3) Liquid refrigerant in compressor at start-up (indicated by

abnormally cold compressor shell)

Recommended ActionReplace compressor

Check and adjust superheat

Check for refrigerant overcharge

H. System Short of Capacity

Probable Cause(1) Low refrigerant charge (indicated by high superheat and low

subcooling)(2) Clogged filter drier (indicated by temperature change in

refrigerant line through drier)(3) Incorrect expansion valve setting(4) Expansion valve stuck or obstructed(i.e., high superheat and

high water temperature)(5) Low evaporator water flow(6) Noncondensibles in system

(7) Leaky valves in compressor (i.e., operation at abnormally highsuction and low discharge pressures)

Recommended ActionAdd refrigerant

Replace filter drier or filter drier core

Readjust expansion valveRepair or replace expansion valve

Check strainers. Adjust water flowEvacuate and recharge system

Replace compressor

I. Suction Pressure Too Low

Probable Cause(1) Shortage of refrigerant (i.e., high superheat, low subcooling)(2) Thermostat set too low (i.e., low discharge pressure, low leaving

water temperature)(3) Low water flow(4) Clogged filter drier(5) Expansion valve power assembly has lost charge

(6) Obstructed expansion valve (i.e., high superheat)

Recommended ActionFind and repair leak; recharge systemReadjust thermostat

Check for clogged strainers and ncorrect balancing valve settingsCheck for frost on filter drier. Replace if neededRepair or replace expansion valve power head assembly

Clean or replace valve

J. Suction Pressure Too High

Probable Cause(1) Excessive cooling load (i.e., high supply water temperatures)(2) Expansion valve overfeeding (i.e.,superheat too low, liquid

flooding to compressor)(3) Suction valves broken (i.e. noisy compressor)

Recommended ActionSee (E) aboveAdjust superheat setting; verify that remote bulb is properly attachedto suction lineReplace compressor


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31 CGA-SVX01B-EN

K. Discharge Pressure Too Low

Probable Cause(1) Shortage of refrigerant (i.e., low subcooling, high superheat,

bubbles in sight glass)(2) Broken or leaky compressor discharge valves(3) Defective low pressure switch(4) Unit running below minimum operating ambient

Recommended ActionFind and repair leak; recharge system

Replace compressorReplace defective controlProvide adequate head pressure controls, or an ambient lockoutswitch

L. Discharge Pressure Too High

Probable Cause(1) Too little or too warm condenser air; airflow restricted(2) Air or non-condensable gas in system (i.e., exceptionally hot

condenser)(3) Refrigerant overcharge (i.e., high subcooling, low superheat,

high suction pressure)(4) Excessive system load(5) Defective condenser fan or fan pressure control (i.e., 1 fan off,

high condenser pressure)

Recommended ActionClean coil; Check fans and motors for proper functionEvacuate and recharge system

Recover excess refrigerant

Reduced loadRepair or replace switch

M. System Cannot Heating Mode (CGAR Model Only)

Probable Cause(1) Broken or improper control wiring(2) Defective four-way valve

Recommended ActionCheck control wiringReplace four-way valve

N. Suction Pressure Too Low - Heating Mode (CGAR Model Only)

Probable Cause(1) Low refrigerant charge(2) Too little or too cold evaporator air; airflow restricted(3) Unit running below minimum operating ambient(4) Expansion valve power assembly has lost charge

Recommended ActionAdd refrigerantClean coil; Check fans and motors for proper functionProvide an ambient lockout switchRepair or replace expansion valve power head assembly

O. Discharge Pressure Too High - Heating Mode (CGAR Model Only)

Probable Cause(1) Low water flow(2) Defective heating thermostat switch

Recommended ActionCheck for clogged strainers and incorrect balancing valve settingsa. Verify that sense bulb is properly inserted bulbwell of

heat-exchangerb. Replace heating thermostat switch


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Literature Order Number

File Number

Supersedes

Stocking location

CGA-SVX01B-EN-0404

CGA-IOM-7

CGA-SVX01A-EN-0701

Taipei, Taiwan

ISO 9001 Qualified factory - Trane TaiwanFM 38631

North American Group The Trane Company 3600 Pammel Creek Road La Crosse, Wl 54601-7599

http : // www.trane.com

Documents

Cga Svx01b en 0404 Trane