Problem Recommended Troublshooting Steps
Fan does not run with ventilation
activated. Compressor runs briefly
but cycles on & off with humidity
controlturnedtoON.
1. Loose connection in fan circuit.
2. Obstruction prevents fan rotation.
3. Defective fan.
4. Defective fan relay.
5. Defective fan capacitor.
Evaporator coil frosted continu-
ously,lowde-humidifyingcapac-
ity.
1. Defrost thermostat loose or defective.
2. Low refrigerant charge.
3. Dirtyairfilter(s)orairflowrestricted.
Unit not providing ventilation. 1. Checkcontrolwireconnections(checkconnectionsatfreshairdamper
also).
2. Defective fresh air damper.
3. Dirty air intake. Clean outside intake hood.
Unitremovessomewater,butnot
asmuchasexpected. 1. Airtemperatureand/orhumidityhavedropped.
2. Humidity meter and or thermometer used are out of calibration.
3. Unit has entered defrost cycle.
4. Airfilterdirty.
5. Defective defrost thermostat.
6. Low refrigerant charge.
7. Airleaksuchasloosecoverorductingleaks.
8. Defective compressor.
9. Restrictive ducting.
10.OptionalCondensatePumpSafetySwitchopen.
UnitTesttodetermineproblem: 1. Detach field control wiring connections from main unit.
2. Connect the yellow and green pigtails from the main unit together; only
the impeller fan should run. Disconnect the wires.
3. Connect the yellow and blue pigtails from the main unit together; the
compressor and impeller fan should run.
4. Ifthesetestswork,themainunitisworkingproperly.Youshouldcheck
thecontrolpanelandfieldcontrolwiringforproblemsnext.
5. Removethecontrolpanelfromthemountingboxanddetachitfromthe
fieldinstalledcontrolwiring.Connecttheblue,yellow,andgreenwires
from the control panel directly to the corresponding colored pigtails on the
mainunit.Leavetheviolet,white,andredwiresdisconnected!
6. Turn on the fan switch; the impeller fan should run. Turn off the fan switch.
7. Turn on the humidity control; the compressor and impeller fan should run.
8. Ifthesetestswork,theproblemismostlikelyinthefieldcontrolwiring.
Refrigerant Charging
Iftherefrigerantchargeislostduetoserviceoraleak,anewchargemustbeaccuratelyweighedin.Ifanyofthe
oldchargeisleftinthesystem,itmustberecoveredbeforeweighinginthenewcharge.Refertotheunitnameplate
for the correct charge weight and refrigerant type.
Compressor/Capacitor Replacement
Thiscompressorisequippedwithatwoterminalexternaloverloadandaruncapacitor,butnostartcapacitoror
relay.
Troubleshooting