Haier RF-8888-279, Service Manual

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3) Refrigerating system is clogged with dirt
Analysis of Trouble
Coarse-grained dirt and refrigerant oil in the system tend to settle and clog the capillary
inlet. Flow of refrigerant stops when the filter screen is completely clogged by dirt. This
condition has the same symptoms as when the refrigerating system is clogged by ice.
However, when you heat the clogged area with a hot towel, there is no reaction. After
rejecting the possibility of ice clogging, it can be concluded that the clogging is due to dirt.
Remedy
Dismantle the system. Remove the dry filter and purge the tubing with nitrogen. Next,
install a new filter. Then evacuate it and fill with refrigerant.
4) Clogged filter
Analysis of Trouble
The complete clogging of the filter rarely occurs. Oftentimes, there is an accumulation of
paste-like matter formed from dust on the filter. Tapping the filter may remove part of the
paste-like matter. When the filter is clogged, it will be cooler than normal.
Remedy
The same as described for the capillary clogged with dirt.
Troubles of Compressor
1) Broken gas suction and discharge valve blocks
Analysis of Trouble
The compressor works by opening and closing the gas suction valve and discharge valve to
suck and discharge the refrigerant. If the valve block is broken, the refrigerant cannot be
discharged. This prevents refrigeration.
Remedy
It is quite difficult to differentiate this trouble from others because they have similar
symptoms. When repairing, listen attentively for abnormal sounds coming from the
compressor. Oftentimes, broken pieces of valve block strike against the cylinder. Check to
see if the compressor casing is too hot. Secondly, measure the pressures at the high and
low-pressure ports of the compressor with pressure gauges. If the gas suction valve block is
broken, the suction pressure gauge pointer will swing violently and the suction pressure will
be very high. Whereas when the gas discharge valve block is broken, the discharge pressure
gauge pointer will swing drastically and the discharge pressure will be very high. In both
cases, stop the compressor at once. If possible, open the cylinder cover, check the valve
block, and repair it.
Compressor suddenly stops
Very often, when the compressor suddenly stops, the gas suction pressure and/or discharge
pressure have exceeded their respective prescribed ranges. When this happens, the
pressure-operated protective relay automatically shuts off the power to the compressor.
Below we discuss the reasons for high gas discharge pressure and low suction pressure.
Stoppage due to excessively high gas discharge pressure
1) High gas discharge pressure due to excess refrigerant
Analysis of Trouble