Kubota KX080-4 Workshop Manual page 471

KX080-4, WSM
Refrigerant fails to circulate
1. Symptoms that appear in the refrigerant cycle
• Low-pressure side (1) becomes a vacuum and the
high-pressure side (2) is at low pressure.
Low-pressure side (1) : Vacuum;
High-pressure side (2) : 0.49 to 0.59 MPa (5 to 6 kgf/cm
71.2 to 85.3 psi)
2. Possible Causes
• The line above the expansion valve orifice is frozen up and
the refrigerant cannot flow due to moisture and/or dirt stuck
in the refrigerant cycle.
3. Solution Methods
Wait for some time to elapse and determine whether it is dirt or
moisture blocking the line by whether A/C operation recovers or
not.
• If the problem is moisture, the problem resolves itself, as
indicated in the previous section.
• If the cause is dirt, remove the expansion valve and blow out
any dirt with compressed air.
• If the dirt cannot be eliminated, replace the expansion valve
and the receiver. Vacuum out the line and charge the cycle
with an appropriate amount of fresh refrigerant.
• If the problem is caused by a gas leak in the heat-sensitive
tube, replace the expansion valve.
(1) Low Pressure Side
Expansion valve too far open
1. Symptoms that appear in the refrigerant cycle
• Both high (2) and low (1) side pressures are too high.
Low-pressure side (1) : 0.29 to 0.39 MPa (3 to 4 kgf/cm
42.7 to 56.9 psi)
High-pressure side (2) : 1.96 to 2.45 MPa (20 to 25 kgf/cm
284.5 to 355.6 psi)
• Either frost or heavy condensation on the low-pressure side
line
2. Possible Causes
• Problem with the expansion valve.
• The flow volume adjustment is set improperly.
3. Solution Methods
• Replace the expansion valve.
(1) Low Pressure Side
Faulty compression from compressor
1. Symptoms that appear in the refrigerant cycle
• Low-pressure side (1) : 0.39 to 0.59 MPa (4 to 6 kgf/cm
56.9 to 85.3 psi)
High-pressure side (2) : 0.69 to 0.98 MPa (7 to 10 kgf/cm
99.6 to 142.2 psi)
2. Possible Causes
• Compressor is leaking.
3. Solution Methods
• Replace the compressor.
CAUTION
• When the compressor is producing a faulty compression, it
can be detected with a manifold gauge (figure at left).
(1) Low Pressure Side
5-S14
(2) High Pressure Side
RY9212001CAS0023US0
(2) High Pressure Side
RY9212001CAS0024US0
(2) High Pressure Side
RY9212001CAS0025US0
KiSC issued 08, 2015 A
CABIN
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