Quantum 67ACW2-134, Owner'S Manual

Owners Manual 

Quantum Energy Technologies

6m.1: Trouble Shooting Chart 

PROBLEM 

POSSIBLE CAUSES 

POSSIBLE CORRECTIVE STEPS 

COMPRESSOR 
WILL NOT RUN 
 

1.  Main switch open 
2.  Fuse blown, breakers open 
 
 
3.  Thermal overloads tripped 
4.  Defective contactor or coil 
5.  System off by protection device 
6.  No heating required 
7.  Liquid line solenoid will not open 
8.  Motor electrical problem 
9.  Loose wiring, faulty controller sensor 

/ broken wire 

10. Compressor  failure 

1. Close 

switch 

2. Check 

electrical 

circuits and motor windings for shorts. 

Check for overloads and loose connections.  Replace 
fuse or reset breaker. 

3. 

Check unit when back on line, auto reset 

4. Repair 

or 

replace 

5. 

Determine cause and correct 

6. 

None, should start on call for heating 

7. 

Repair or replace coil 

8. 

Check motor for open or short circuit, or burnout 

9. 

Check all wire junctions. Tighten all terminals 

 
10. Replace compressor 

COMPRESSOR 
NOISY OR 
VIBRATING 

1.  Refrigerant flooding compressor 
2. Refrigerant overcharged 
3.  Improper line support 
4. Worn compressor 

1. 

Check expansion valve setting and superheat 

2. Remove 

excess 

refrigerant 

3. 

Relocate or add supports 

4. Replace 

compressor 

EVAPORATOR COIL 
ICING UP  

1.  Lack of refrigerant 
2.  Restricted air or cold air re-circulated
3.  Expansion valve not opened 

sufficiently 

4.  Expansion valve power element 

leaks 

5.  De-ice interval too long for that 

particular site 

6.  Too much cold water to be heated 

1. 

Check for leaks. Repair and replace refrigerant. 

2. 

Proper clearance for air flow 

3. 

Check and adjust for proper superheat 

 
4. 

Replace expansion valve 

 
5. 

Shorten the de-ice interval 

 
6. 

Reduce the amount of water or add a head pressure 
regulator to the machine 

1.  Compressor loses oil owing to 

refrigerant flooding back 

2.  Compressor loses oil owing to 

refrigerant leaks 

3.  System contaminated, and/or Liquid 

injection capillary tube blocked 

4.  Suction superheat too high 
5.  Oil degrades owing to high 

temperature 

COMPRESSOR 
THERMAL SWITCH 
OPEN 

 
6.  De-icing could not de-ice completely. 
7.  Crankcase heater burned out 

1. 

Check and fix the flood back problem. Add oil if 
necessary 

2. 

Find and repair the leakage. Add oil if necessary 

 
3. 

Purging the system and change oil and the filter/drier 

 
4. Adjust 

superheat 

5. 

Find and rectify the high discharge temperature. Change 
the oil (to the requirement amount!) purge the system 
and change the filter/drier 

6. 

Find and rectify the de-ice problem 

7. 

Replace crankcase heater 

HIGH 
DISCHARGE 
PRESSURE 

1.  Non condensibles in system 
2. Refrigerant overcharged 

1. 

Remove with authorized procedures 

2. Remove 

excess 

charge 

3.  Water temp cut-out setting too high 

3. 

Check the settings 

4.  Condenser water tube scaled 

4. 

Clean the tube 

5. Blocked condenser 

5. Clean 

condenser 

6.  Higher suction pressure than normal 

6. 

Refer to ‘High Suction Pressure’ 

1.  Lack of refrigerant 

1. 

Check for leaks. Repair then replace refrigerant. 

2. Evaporator dirty 

2. Clean 

evaporator 

3.  Clogged filter drier (pipe after the 

filter cold) 

3. 

Replace filter drier 

LOW SUCTION 

PRESSURE 

4.  Expansion valve malfunctioning 

(leakage phial/bulb) 

4. 

Check and change it 

5.  De-icing could not de-ice completely 

5. 

Check and adjust the de-icing setting if necessary. 

UNSTABLE 
SUCTION 

1. Expansive valve hunting 

1. 

Check and close the valve for proper superheat 

2.  Ice-blocking in the expansion valve 

(ice up in the Valve body) 

2. 

Check and change the refrigerant and the drier 

PRESSURE 
UNSTABLE 
DISCHARGE 

1.  Non condensibles in system 

1. 

Remove with authorized procedures  

2. Refrigerant overcharged 

2. Remove 

excess 

charge 

PRESSURE 
COMPRESSOR 
INTERVAL TOO 
SHORT 

1. Erratic water thermostat 

1. Replace 

sensor 

2.  Insufficient water flow 

2. Adjust 

flow 

1.  Low voltage during high loads 

1. 

Check supply voltage 

MOTOR 

2.  Defective or grounded motor wiring 

2. Replace 

compressor 

OVERLOAD 

3. Loose power wiring 

3. 

Check all connections and tighten 

RELAYS OPEN 

4.  High evaporating temperature 

4. 

See steps for high discharge 

OR BLOWN 

5.  Liquid refrigerant flood back 

5. 

Too much refrigerant. Check the evaporator, the fan and 
the TX valve opening. 

FUSES 

6. Unbalanced voltage 

6. 

Check voltage. Contact Power Company 

Document Number : QDC0049PD-5 

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