TROUBLE SHOOTING CHART
SYMPTOM
CAUSES
CHECK & CORRECTIVE MEASURE
1. Low suction pressure
2. High discharge pressure
3. Less air quantity
4. Cooling coil ices up
5. Second stage (If exists) not working
6. Serving large area
1. Low ambient condition
2. Safety low pressure switch open due to low
suction pressure
3. Fan cycling (whenever applicable) setting low
4. Thermostat setting too low
5. Cooling coil ices-up
6. Less air quantity
1. High discharge pressure
2. High thermostat setting
3. Serving large area
4. Less air quantity
5. High ambient condition
6. Dirty condenser
1. Less freon
2. Less air quantity
3. Dirty filter
4. Dirty cooling coil
1. Safety circuit open due to low pressure switch
1. Thermostat in cold location
1. Imbalance freon
2. Malfunctioning pumpdown solenoid valve
1. Leaky pumpdown solenoid valve
1. Improper installation
2. Improper vibration isolators
3. Loose parts or mountings
4. Tubing rattle
5. Bent fan blade causes vibration
6. Defective bearings
7. Belt tension is high
8. Blower motor pulley is not aligned
1. Improper installation
2. Improper vibration isolators
3. Abnormal noise in the unit
4. Unit too close to the slab/wall openings
5. Duct design (high static)
6. Wooden packing beneath the compressor is not removed
1. Low voltage
2. Single phase failure
3. Burned wirings
4. Overload protector open
5. Defective contactor
6. Burned compressor motor winding
7. Damaged (stuck) compressor
1. Burned wirings
2. Grounded wirings
3. Faulty field wiring
4. Grounded compressor/blower motor
5. Undersize circuit breaker
1. Verify the reason & correct it (refer to symptom
for "low suction pressure").
2. Verify the reason and adjust the freon, if required.(refer
to symptom for "high discharge pressure").
3. Refer to symptom for "blower works, less air".
4. Determine the reason (refer to symptom for
"cooling coil ice up") & correct it.
5. Set the thermostat to lower temperature (21
0
C)/
or verify the reason.
6. Check the design.
1. Check and verify the ambient temperature.
2. Check the reason and correct it (refer to
symptom for "low suction pressure").
3. Adjust the fan cycling.
4. Adjust the thermostat setting.
5. Verify the reason and correct it (refer to
symptom for "cooling coil ice up").
6. Verify the reason and correct it (refer to
symptom for "blower works, less air").
1. Check and verify the reason (refer to symptom
for "high discharge pressure").
2. Adjust thermostat.
3. Check the design/unit selection.
4. Check and verify the reason (refer to symptom
for "blower works, less air").
5. Check the ambient condition.
6. Clean it.
1. Check for gas leak & charge freon as required.
2. Determine the reason and correct it (refer to
symptom for "blower works, less air").
3. Clean it.
4. Clean it.
1. Rectify the reason of low suction pressure (refer
to symptom for "low suction pressure").
1. Shift the location as required.
1. Check freon charge and confirm FLA.
2. Check pumpdown solenoid valve operation.
1. Check pumpdown solenoid valve and replace it.
1.Check and correct it properly.
2. Check and correct it properly.
3. Check and tighten.
4. Tighten the pipe support.
5. Check the balance, alignment, bracket, etc.
Correct it/replace it.
6. Replace the motor.
7. Adjust belt tension.
8. Align pulley.
1. Check and correct it.
2. Check and correct it.
3. Verify the reason of noisy unit & correct it.
4. Verify the design/Relocate the unit if necessary.
5. Check & verify the design.
6. Remove wooden packing (if any).
1. Rectify the reason & correct it.
2. Check the compressor amperage each phase.
3. Check and correct it.
4. Check and verify the reason.
5. Check and replace it.
6. Check and replace it.
7. Check and replace it.
1. Check and correct the wiring.
2. Check meggar test.
3. Check wiring against diagram.
4. Replace it, if required.
5. Check the circuit breaker ratings.
Unit works continuously, no sufficient
cooling
Unit not cooling properly during night
time
Not sufficiently cooling during
daytime
Cooling coil ices up
Unit is not restarting (after a cut-off)
Unit is taking long time to restart
Compressor goes lockout (pump
down system)
Taking more time for the pumpdown
cycle, cooling coil ices up
Noisy unit
Unit operational noise listening inside
the building
Compressor not working
Circuit breaker of the unit trips
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