Specifications

104
MVCU -2009 Troubleshooting
Diagnostic Guidelines
By means of pressure readings:
Data
Circuit
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 (e.g. air)
3. Obstructed air-intake / discharge.
4. Hot air short circuiting in outdoor unit.
High side
Low side
•
•
1. Poor compression /no compression (compressor
defective)
2. Reversing valve leaking.
High side
Low side
•
•
1. Undercharged with refrigerant.
2. Refrigerant leakage.
3. Air fi lter clogged / dirty (indoor unit).
4. Indoor fan locked / seized.
5. Defective defrost control, outdoor coil freeze up
(heating).
6. Outdoor fan locked / seized (heating).
High side
Low side
•
•
1. Outdoor fan blocked (cooling).
2. Outdoor coil dirty (cooling).
3. Indoor fan locked / seized (heating).
4. Indoor air fi lter 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.
13_Troubleshooting.indd 10413_Troubleshooting.indd 104 4/28/2009 11:30:57 AM4/28/2009 11:30:57 AM