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TROUBLESHOOTING (cont)PROBLEM SOLUTION
COMPRESSORCYCLES ON LOW-PRESSURE SWITCH
Indoor-AirFan Running
1. Li quid line soleno id valve(s) fai ls to open. 1. Check liquid line solenoid valve(s) for proper operation. Replace if necessary.
2. Filter drier plugged. 2. Replace filter drier.
3. Expansion valve power head defective. 3. Replace power head.
4. Lowr efrigerantcharge. 4. Add charge.Check low-pressure switchsetting.
AirflowRestricted
1. Coiliced up. 1. Check refrigerantcharge.
2. Coil dirty. 2. Clean coil fins.
3. Air filters dirty. 3. Clean or replace filters.
4. Dampersclosed. 4. Checkdamper operationand position.
Indoor-AirFan Stopped
1. Electrical connectionsloose. 1. Tighten all connections.
2. Fanrelay defective. 2. Replace relay.
3. Motor overload open. 3. Power supply.
4. Motordefective. 4. Replacemotor.
5.Fanbeltbrokenorslipping. 5.Replaceortightenbelt.
COMPRESSORRUNNING BUT COOLING INSUFFICIENT
SuctionPressure Low
1. Refrigerantcharge low. 1.Add refrigerant.
2. Head pressure low. 2. Check refrigerant charge. Ch eckoutd oor-airfan thermostat settings.
3. Air filters dirty. 3. Clean or replace filters.
4. Expansion valve power head defective. 4. Replace power head.
5. Indoor coilpartially iced. 5. Check low-pressuresetting.
6. Indoorairf lowrestricted. 6. Remove obstruction.
SuctionPressure High
1. Heat load excessive. 1. Check for open doors or windows in vicinity of fan coil.
UNITOPER ATES TOO LONGOR CONTINUOUSLY
1. Lowrefrigerant charge. 1.Add refrigerant.
2. Control contactsfused. 2. Replacecontr ol.
3. Air in system. 3.Purge a nd evacuate system.
4. Partially p lugged expansion valve or filter d rier. 4. Clean or r eplace.
SYSTEM IS NOISY
1. Piping vibration. 1.Support piping as required.
2. Compressor noisy. 2. Replace compressor if bearings are worn.
COMPRESSORLOSES OIL
1. Leakin system. 1. Repairleak.
2. Crankcase heaters not energized during shutdown. 2. Check wiring and relays. Check heater and replace if defective.
3. Improper inter connecting piping design. 3. Check pipin g for oilr eturn. Replace if necessary.
FROSTEDSUCTION LINE
Expansionvalve admitting excess refrigerant. Adjustexpansion valve.
HOTLIQU ID LINE
1. Shortage of refrigerant due to leak. 1. Repair leak and recharge.
2. Expansion valve openstoo wide. 2. Adjust expansion valve.
FROSTEDLIQUIDLINE
1. Restricted filter drier. 1.Remove restriction or replace.
2. Liqu id line solenoid valve partially closed. 2. Replace valve.
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