Troubleshooting Chart - McQuay SEASONCON ALP-037A Manual

PROBLEM
1. Main switch open,
2. Fuse blown. Circuit breakers open.
3. Thermal overloads tripped.
Compressor will
4. Defective contactor or ~011.
not run
5. System shut down by safety devices.
6. No cooling required.
7. Liquid line solenotd will not open.
8. Motor electrical trouble
9. Loose wiring.
1. Flooding of refrigerant into crankcase.
Compressor noisy
2. Improper piping support on suction or
or vibrating liquid Irne.
3. Worn compressor
1. Non-condensibles in system.
2. System overcharged with refrigerant.
High Discharge
3. Discharge shut off valve partially closed.
Pressure
4. Fan not running.
1. Faulty condenser temperature regulation.
2. Sucticn shut-off valve partially closed.
Low Discharge
3. Insufficient refrigerant in system.
Pressure 4. Low suction pressure.
5. Compressor operating unloaded.
1. Excessive load.
High Suction 2. Expansion valve overfeeding.
Pressure 3. Compressor unloaders open.
1. Lack of refrigerant.
2. Evaporator dirty. Plugged air filters.
3. Clogged liquid line filterdrier.
4. Clogged suction line or compressor suction.
Low Suction
gas strainers.
Pressure
5. Expansion valve malfunctioning.
6. Condensing temperature too low.
7. Compressor will not unload.
Compressor will not 1. Defective capactty control.
unload or load up. 2. Pressurestat not set for application.
1. Clogged suction oil strainer.
2. Excessive liquid in crankcase.
3. Oil pressure gauge defective.
4. Low 011 pressure safety switch defective.
Little or no oil
5. Worn 011 pump.
pressure
6. 011 pump reversing gear stuck in wrong
7. Worn bearings.
8. Low oil level.
9. Loose fitting on oil lines.
10. Pump housing gasket leaks.
11. Flooding of refrigerant into crankcase.
Compressor loses 1. Lack of refrigerant.
oil 2. Excessive compression ring blow-by.
1. Low voltage during high load conditions.
2. Defective or grounded wiring in motor.
3. Loose power wirtng.
Motor overload 4. High condensing temperature.
5. Power Itne fault causing unbalanced voltage.
relays open or
blown fuses
6. High amblent temperature around the over-
load relay.
7. Failure of second starter to pull in on part-
winding start systems.
1. Operating beyond design conditions.
Compressor thermal
protector switch
2. Discharge valve parttally shut.
open.
3. Blown valve plate gasket.
TROUBLE SHOOTING CHART
POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS
1. Close switch.
2. Check electrical circuits and motor wlnding for shorts
or grounds. Investigate for possible overloading. Re-
place fuse or reset breakers after fault is corrected.
3. Overloads are auto. reset. Check unit closely when
unit comes back on line.
4. Repair or replace.
5. Determine type and cause of shutdown and correct it
before resetting safety switch.
6. None. Wait until unit calls for cooling.
7. Repair or replace ~011.
8. Check motor for opens, short circuit, or burn out.
9. Check all wire junctions. Tighten all terminal screws.
1. Check setting of expansion valve.
2. Relocate, add or remove hangers.
3. Replace.
1. Purge the non-condensibles.
2. Remove excess.
3. Open valve.
4. Check electrical circuit.
1. Check condenser control operation.
2. Open valve.
3. Check for leaks. Repair and add charge.
4. See Corrective Steps for low suction pressure below.
5. See Corrective Steps for failure of compressor to load
up below.
1. Reduce load or add additional equipment.
2. Check remote bulb. Regulate superheat.
3. See Corrective Steps below for failure of compressor
to load up.
1. Check for leaks. Repair and add charge.
2. Clean chemically.
3. Replace cartrIdge(
4. Clean strainers.
5. Check and reset for proper superheat.
6. Check means for regulating condensing temperature.
7. See Corrective Steps for failure of compressor to
unload.
1. Replace.
2. Reset pressurestat setting to fit application.
1. Clean.
2. Check crankcase heater. Reset expansion valve for
higher superheat. Check liquid line solenoid valve
operation.
3. Repair or replace. Keep valve closed except when
taking readings.
4. Replace.
5. Replace.
6. Reverse direction of compressor rotation.
7. Replace compressor.
8. Add oil.
9. Check and tighten system.
10. Replace gasket.
11. Adjust thermal expansion valve.
1. Check for leaks and repair Add refrigerant.
2. Replace compressor.
1. Check supply voltage for excessive line drip.
-
2. Replace compressor motor.
3. Check all connections and tighten.
4. See Corrective Steps for high discharge pressure.
5. Check supply voltage. Notify power compnay. Do not
start until fault IS corrected.
6. Provide ventilation to reduce heat.
7. Repair or replace starter or tome delay mechanism.
1. Add facilities so that conditions are within allowable
2. Open valve.
3. Replace gasket.
FORM NO. 364897Y
PAGE 43