McQuay MWM Service Guide Book

57
General Troubleshooting Guide
By means of pressure readings.
Pressure Probable Cause
Too Low
A Little Low
Normal
A Little High
Too High
High Side
Low Side
1. Overcharged with refrigerant.
2. Non-condensable gases in refrigerant circuit
(eg. Oil)
3. Obstructed air-intake / discharge.
4. Short circuit of hot air at condensing unit.
High Side
Low Side
1. Poor compression / no compression
(compressor defective).
2. Check valve stick in open position.
3. Reversing valve leaking (for heatpump only).
High Side
Low Side
1. Undercharged with refrigerant.
2. Refrigerant leakage.
3. Air filter clogged / dirty (indoor unit).
4. Indoor fan locked (cooling).
5. Defective defrost control, outdoor coil freeze
up (heating).
6. Outdoor fan locked (heating).
High Side
Low Side
1. Outdoor fan blocked (cooling).
2. Outdoor coil dirty (cooling).
3. Indoor fan locked (heating).
4. Indoor filter clogged dirty (heating).
High Side
Low Side
1. Air intake temperature of indoor unit too high.
Data
Circuit

McQuay MWM Specifications

General

Brand	McQuay
Model	MWM
Category	Air Conditioner
Language	English