McQuay WGS190AW User Manual

96 WGS 130A to 190A OM WGS-5
PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS
Low Suction
Pressure
1. Lack of refrigerant.
2. Evaporator dirty.
3. Clogged liquid line filter-drier.
4. Expansion valve malfunctioning.
5. Condensing temperature too low.
6. Compressor will not unload.
7. Insufficient water flow.
1. Check for leaks. Repair and add charge.
2. Clean chemically.
3. Replace cartridge(s).
4. Check and reset for proper superheat.
Replace if necessary.
5. Check means for regulating condensing
temperature.
6. See corrective steps for failure of
compressor to unload.
7. Adjust flow.
Little or No Oil
Pressure
1. Clogged suction oil strainer.
2. Excessive liquid in crankcase.
3. Low oil level.
4. Flooding of refrigerant into crankcase.
1. Clean.
2. Check sump heater. Reset expansion
valve for higher superheat. Check liquid
line solenoid valve operation.
3. Add oil.
4. Adjust expansion valve.
Compressor
Loses Oil
1. Lack of refrigerant.
2. Velocity in risers too low (A-C only).
3. Oil trapped in line.
1. Check for leaks and repair. Add
refrigerant.
2. Check riser sizes.
3. Check pitch of lines and refrigerant
velocities.
Motor Overload
Relays or Circuit
Breakers Open
1. Low voltage during high load conditions.
2. Defective or grounded wiring in motor or
power circuits.
3. Loose power wiring.
4. High condensing temperature.
5. Power line fault causing unbalanced
voltage.
6. High ambient temperature around the
overload relay
1. Check supply voltage for excessive line
drop.
2. Replace compressor-motor.
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.
6. Provide ventilation to reduce heat.
Compressor
Thermal Switch
Open
1. Operating beyond design conditions.
2. Discharge valve partially shut.
1. Add facilities so that conditions are within
allowable limits.
2. Open valve.
Freeze Protection
Opens
1. Thermostat set too low.
2. Low water flow.
3. Low suction pressure.
1. Reset to 42°F (6°C) or above.
2. Adjust flow.
3. See “Low Suction Pressure.”

McQuay WGS190AW Specifications

General

Brand	McQuay
Model	WGS190AW
Category	Chiller
Language	English