Doosan DX225LC, Manual, Page: 110 / 136

Electrical System
Page 109
SP000935
4
High-pressure: Over 6 kg•cm
2
(85 psi)
Low-pressure: Approximately 760 mmHg (Negative Pressure)
Possible Cause: Refrigerant does not circulate
Step Inspection Item Remedy
1
1. Connect manifold gauge and start engine.
2. Turn on air conditioner.
3. Set blower switch to HIGH position.
4. Turn air conditioner OFF and wait 10
minutes.
5. Recheck high / low-pressure readings.
High-pressure: 13.0 - 19.0 kg•cm
2
(185 - 270 psi)
Low-pressure: 1.5 - 3.3 kg•cm
2
(21.3 - 46.9 psi)
Yes
Moisture in system, replace receiver
dryer.
No
Contaminated system, replace
expansion valve.
(Replace evaporator core assembly.)
5
High-pressure: Over 6 - 18 kg•cm
2
(85 - 256 psi)
Low-pressure: 500 mmHg (Negative Pressure) - Dial indicator needle unstable.
Possible Cause: Moisture in system has iced up the expansion valve.
NOTE:
When the absorbed moisture freezes the pressure readings may look normal. Careful readings
should be made to determine whether pressure is in normal range.
1. Recover any remaining refrigerant.
2. Vacuum out system.
3. Recharge system.
NOTE:
If the system has been exposed to the air for a long time, replace the receiver dryer.
6
High-pressure: Over 22.0 - 23 kg•cm
2
(313 - 327 psi)
Low-pressure: 2.5 kg•cm
2
(36 psi)
Possible Cause: Refrigerant pressure problem because of defective expansion valve or temperature sensor.
Step Inspection Item Remedy
1
Inspect whether the temperature sensor is
installed properly.
Yes Replace expansion valve.
No Exchange duct sensor.
7
High-pressure: Over 7.0 - 11.0 kg•cm
2
(100 - 156 psi)
Low-pressure: 4.0 - 6.0 kg•cm
2
(57 - 85 psi)
Possible Cause: Low refrigerant pressure because of poor compressor compression.
Inspect and replace compressor if necessary.