Troubleshooting Chart - McQuay seasoncon ALP-067A Installation And Maintenance Data

Trouble Shooting Chart
PROBLEM
Compressor will
not run
Compressor noisy
or vibrating
High Discharge
Pressure
Low Discharge
Pressure
High Suction
Pressure
Low Suction
Pressure
Compressor will not
unload or load up.
Little or no oil
pressure
Compressor loses
oil
Motor overload
relays or circuit
breakers open
Compressor thermal
protector switch
open.
page 42
POSSIBLE CAUSES
1. Main switch open.
2. Fuse blown. Circuit breakers open.
3. Thermal overloads tripped.
4. Defective contactor or coil.
5. System shut down by safety devices.
6. No cooling required.
7. Liquid line solenoid will not open.
8. Motor electrical trouble
9. Loose wiring.
I. Flooding of refrrgerant Into crankcase.
2. Improper piping support on suction or
liquid line.
3. Worn compressor
1. Non-condensibles in system.
2. System overcharged with refrigerant.
3. Discharge shut off valve partially closed.
4. Seasontrol out of adjustment
5. Fan not running.
2. Suction shut-off valve partially closed.
3. insufficient refrrgerant in system.
4. Low suction pressure.
5. Compressor operating unloaded.
1. Excessive load.
2. Expansron valve overfeedrng.
3. Compressor unloaders open.
1. Lack of refrigerant.
2. Evaporator dirty. Plugged acr filters.
3. Clogged liqurd lrne filterdrier.
4. Clogged suction line or compressor suction.
gas strainers.
5. Expansion valve malfunctioning.
6. Condensing temperature too low.
7. Compressor will not unload.
1. Defective capacrty control.
2. Pressurestat not set for application.
1. Clogged suction oil strainer.
2. Excessive liquid rn crankcase.
3. Oil pressure gauge defective.
4. Low oil pressure safety switch defective.
5. Worn 011 pump.
6. Oil pump reversing gear stuck in wrong
position.
7. Worn bearrngs.
8. Low oil level.
9. Loose fitting on oil lines.
10. Pump housing gasket leaks.
11. Flooding of refrigerant into crankcase.
1. Lack of refrrgerant.
2. Excessive compression ring blow-by.
1. Low voltage during high load conditions.
2. Defective or grounded wring in motor.
3. Loose power wiring.
4. High condensrng temperature.
5. Power line fault causing unbalanced voltage.
6. High ambient temperature around the over-
load relay.
7. Failure of second starter to pull in on part-
winding start systems.
1. Operating beyond design conditions.
2. Discharge valve partially shut.
3. Blown valve plate gasket.
POSSIBLE CORRECTIVE STEPS
1. Close switch.
2. Check electrical circuits and motor winding 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 coil.
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.
I. Purge the non-condensibles.
2. Remove excess.
3. Open valve.
4. Adjust Seasontrot valves.
5. Check belts and electrical crrcuit.
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.
2. Check remote bulb. Regulate superheat.
3. See Corrective Steps below for failure of compressor
to load up.
2. Clean chemrcally.
3. Replace cartridge(s).
4. Clean strarners.
5. Check and reset for proper superheat.
6. Check means for regulating condensing temperature.
7. See Correctrve Steps for failure of compressor to
unload.
2. Reset pressurestat setting to fit applicatron.
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 drrectron of compressor rotation.
7. Replace compressor.
8. Add oil.
9. Check and tighten system.
10. Replace gasket.
11. Adjust thermal expansion valve.
2. Replace compressor.
1. Check supply voltage for excessive lrne 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 time delay mechanism.
I. Add facilities so that conditions are within allowable
limits.
2. Open valve.
3. Replace gasket.