AUX air conditioner service manual
207
tubes, the one connecting discharge pipe of compressor was hot, and other three were also a little hot.
Turned on the air conditioner in heating mode, heating efficiency was also unsatisfactory. So we were
sure that four-way valve had some problems.
Solution: replaced four-way valve, vacuum the system to check leakage sources and finally added
refrigerant.
Experience Conclusion: to fix this kind of faults, we should judge compressor and four-way valve,
which one has problem. Check the pressure and touch the unit with hand to find out fault points. In the
event of gas blowby, temperature difference between inlet and outlet gas is relatively low, gas flow
sound can be heard in valve body, suction force of gas-return pipe of compressor is relatively large
and liquid temperature is relatively high.
Case 13 back valve is broken
Unit Model ：ASW-H12A4/HY
Phenomena ：Seal of back valve is not tight
Cause Analysis: according to client, air conditioner could cool properly, but failed to heat the room.
We turned on the air conditioner, checked the whole unit and found that eudiometer pressure was 14kg,
being relative low, according to fault phenomena, refrigerant in system might be not enough, but we
checked the system and found that balanced pressure was 10kg, and air conditioner could cool normal
in summer, the system didn’t leak, so we presumed that the fault was caused by four-way valve
blowby or poor seal of back valve. Switched on and off four-way valve, valve could operate tightly
and sound of gas discharge was normal. Released refrigerant, vacuumed the system again, added
refrigerant and started the air conditioner again, it still couldn’t work properly. We checked four-way
valve, temperature of its four copper tubes was normal, so we were sure that seal of single-way valve
was not tight, which cause that capillary couldn’t function properly, so the pressure of gas tube was
relative low, and heating efficiency was not so good.
Solution: replaced back valve, vacuum the system and added refrigerant.
Experience Conclusion: back valve can’t close tightly, on high pressure, gas leaks from clearance
between nylon valve block and valve seat, refrigerant fails to enter capillary totally, so air conditioner
fail to produce heat properly, while in cooling mode, single-way valve can work and won’t impact
cooling efficiency.
Case 14 Failed to open the valve enough during installation
Unit Model：ASW-H07B4/HY
Phenomena: Poor cooling efficiency
Cause Analysis: turned on air conditioner for a while, indoor evaporator was frosted, checked the
pressure, it was 3.5kg, relatively low than normal. Added refrigerant and pressure remained
unchanged. Air conditioner continued to work, and after a while, we found that return gas tube of
outdoor unit was frosted, so we presumed that the system was blocked by ice. When we released the
refrigerant, we found that low pressure valve hadn’t opened enough.
Solution: opened the valve fully, adjusted refrigerant pressure to normal value.
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