Komatsu 830E-AC Shop Manual page 966

PROBLEM: Extremely Low Refrigerant Charge in the System
Indications:
Low side pressure - LOW.
High side pressure - LOW.
Discharge air is warm.
The low pressure switch may have
shut off the compressor clutch.
Possible Causes
- Extremely low or no refrigerant in the system.
Possible leak in the system.
PROBLEM: Air and/or Moisture in the System
Indications:
Low side pressure - Normal
High side pressure - Normal
Discharge air is only slightly cool.
(In a cycling type system with a
thermostatic switch, the switch may not cycle
the clutch on and off, so the low pressure
gauge will not fluctuate.)
Possible Causes
Leaks in the system.
N4-40
Suggested Corrective Actions
Check for leaks by performing leak test.
No Leaks Found:
Recover refrigerant from the system. Recharge
using a scale to ensure correct charge. Check
A/C operation and performance.
Leaks Found:
Add refrigerant (make sure system has at least
50% of its normal amount) and leak test system.
It may be necessary to use a jumper wire to
enable the compressor to operate, if the com-
pressor has shut down due to faulty pressure
sensing switch. Repair any leaks and evacuate
the system if necessary, Replace the receiver-drier
if the system was opened. Recharge the system
using a scale and add oil as necessary. Check
AC operation and do system performance test.
Suggested Corrective Actions
Test for leaks, especially around the compressor shaft
seal area. When the leak is found, recover refrigerant
from the system and repair the leak. Replace the
receiver-drier or accumulator because the desiccant
may be saturated with moisture. Check the compressor
and replace any refrigerant oil lost due to leakage.
Evacuate and recharge the system with refrigerant
using a scale. Check A/C operation and performance.
Operator Comfort 10/06 N04031