PROBLEM
POSSIBLE CAUSES
POSSIBLE CORRECTIVE STEPS
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
7. Short
cycling
6.
Check crankcase heater. Reset expansion valve for
higher superheat. Check liquid line solenoid valve
operation.
7.
Stabilize load or increase staging interval.
1.
Lack of refrigerant
1.
Check for leaks and repair. Add refrigerant
2.
Suction superheat too high
2.
Adjust superheat.
Compressor
Loses Oil
3.
Crankcase heater burnout
3.
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
4.
High condenser temperature
5.
Power line fault causing unbalanced voltage
3.
Check all connections and tighten.
4.
See corrective steps for High Discharge Pressure.
5.
Check supply voltage. Notify power company. Do
not start until fault is corrected..
1.
Operating beyond design conditions
2.
Discharge valve partially shut
1.
Add facilities so conditions are within allowable
limits.
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
6.
Compressor bearing failure
5.
Adjust to correct superheat.
6.
Replace compressor .
Warranty Statement
Limited Warranty
All McQuay equipment is sold pursuant to McQuay Standard Terms and Conditions of Sale and
Limited Product Warranty. Consult your local McQuay Representative for warranty details.
Refer to form 933-430285Y-00-A (09/08). To find your local representative, go to
www.mcquay.com
Summary of Contents for McQuay AGZ-D
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