McQuay M5WM 015GR User Manual

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By means of pressure readings :
By Means Of Diagnosis Flow Chart
Generally, there are two kinds of troubles, i.e. starting failure and insufficient cooling/heating. “Starting Failure” is
caused by electrical defect while “Insufficient Cooling/Heating” is caused by improper application or defects in
refrigerant circuit.
i) Diagnosis Of Electric Circuit
No Cooling / Heating
Unit fail to start
Check power supply
- voltage
- phase
- frequency
Check settings of remote control box
Compressor fails to start
Check circuit breake & fuse
Check power source cord
Fan fails to start
Fan Motor Capacitor defective
Loose Connections,
Contactors
Irregular motor resistance ( Ω )
& insulation (M
Ω )
Replace Fan Motor
Compressor Motor damaged ( to replace compressor)
Thermostat setting too high
Protection Device Actuated
Reset
Compressor locked (to replace compressor)
Voltage supply not within range
Check motor resistance ( Ω ) and insulation (M Ω )
Compressor
Capacitor Defective
Loose Connections,
Improper wiring
Regular but fails
to start
Irregular
PRESSURE
PROBABLE CAUSE
Data
Circuit
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 (e.g. oil).
3. Obstructed air-intake/discharge.
4. Short circuiting 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.
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 freezed 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).
5. Non-condensable gases in refrigerant circuit (e.g. air).
High Side
Low Side
1. Air intake temperature of indoor unit too high.

McQuay M5WM 015GR Specifications

General

Brand	McQuay
Model	M5WM 015GR
Category	Air Conditioner
Language	English