Operating instructions
PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS
1. Defective capacity control 1. Replace
2. Faulty thermostat stage or broken wire 2. Replace
Compressor
Will Not Stage
Up
3. Stages not set for application 3. Reset thermostat setting for application
1. Thermostat control band not set properly 1. Set control band wider
2. Erratic water thermostat 2. Replace
Compressor
Staging
Intervals Too
Short
3. Insufficient water flow 3. Adjust flow
4. Rapid load swings 4. Stabilize load
1. Oil hang-up in piping 1. Review refrigerant piping and correct
2. Low oil level 2. Check and add oil
3. Loose fitting on oil line 3. Check and tighten system
4. Level too high 4. Adjust thermal expansion valve
5. Insufficient water flow - Level too high 5. Adjust flow
Compressor Oil
Level Too High
Or Too Low
6. Excessive liquid in crankcase - Level too high 6. Check crankcase heater. Reset expansion
valve for higher superheat. Check liquid line
solenoid valve operation.
7. Short cycling 7. Stabilize load or increase staging interval
1. Lack of refrigerant 1. Check for leaks and repair. Add refrigerant
2. Excessive compression ring blow-by 2. Replace compressor
Compressor
Loses Oil
3. Suction superheat too high 3. Adjust superheat
4. Crankcase heater burnout 4. Replace crankcase heater
1. Low voltage during high load conditions 1. Check supply voltage for excessive line drop
2. Defective or grounded wiring in motor 2. Replace compressor motor
Motor Overload
Relays Or
Circuit Breakers
Open
3. Loose power wiring or burnt contactors 3. Check all connections and tighten
4. High condenser temperature
4. See corrective steps for High Discharge
Pressure
5. Power line fault causing unbalanced voltage 5. Check supply voltage. Notify power
company. Do not start until fault is corrected.
1. Operating beyond design conditions
1. Add facilities so conditions are within
allowable limits
2. Discharge valve partially shut 2. Open valve
3. Blown compressor internal gasket 3. Replace gasket
4. Voltage range or imbalance 4. Check and correct
Compressor
Thermal
Protection
Switch Open
5. High superheat 5. Adjust to correct superheat
6. Compressor bearing failure 6. Replace compressor
70 ACZ / AGZ-BM IMM ACZ/AGZ-4