Maintenance Service and Trouble Shooting
b) Clogged with dirt in capillary
Analysis of Trouble
The capillary inlet is a place where coarse-grained dirt or refrigerant oil in the system
will tend to settle down and clog it. In case considerable dirt accumulates there, the
whole filter screen may be blocked totally, making the refrigerant unable to go through.
Clogging with dirt exhibits the same symptoms as that with ice, namely, higher gas
suction pressure, lower temperature of discharged gas, and no gas flowing sound from
the evaporator. The difference between the both is as follows: if the clogging is
Caused by dirt, tapping the suspicious clogged point (generally in the capillary or the
connection joint of the filter) may cause the refrigerant to flow through partially,
resulting in some corresponding change, whereas in that case if you heat it with a hot
towel, no reaction will happen, no flowing sound can be heard, moreover, there is no
periodic change. After rejecting the possibility of ice clogging, it can be generally
considered as the clogging due to dirt.
Remedy
Dismantle the system, remove the dry filter from it, purge the tubing with nitrogen,
install a new filter, then evacuate it and finally charge it with refrigerant.
C) Clogging in filter
Analysis of Trouble
Total clogging of a filter is rarely to occur. This trouble is mostly caused by the
paste-like matter formed from the substances filled into the system or other dust after
the refrigerator has been used for a longer time, or by the dirt accumulated gradually
inside the filter. Sometimes, tapping the filter nay cause a passage for flowing, touching
it with your hand, you will feel that it is cooler compared with its temperature in the
normal state.
Remedy
The same as described in the capillary clogging with dirt.
3) Troubles of Compressor
a) Breakage of gas suction and discharge valve blocks
Analysis of Trouble
The compressor works by means of the opening and closing of gas suction valve and
discharge valve to suck and discharge the refrigerant. If the valve block is broken, the
refrigerant cannot be discharged, and hence no refrigerating can be achieved.
Method for making judgment
It is quite difficult to differentiate this trouble from others because they often have
similar symptoms. In repairing, firstly, hear attentively if there is some abnormal sound
coming from the compressor (sometimes, the broken pieces of valve block may strike
against the cylinder), and feel the compressor casing with your hand to ascertain
whether it is too hot, this is also helpful to the troubleshooting; 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 is very high, whereas when the gas discharge valve
block is broken , the discharge pressure gauge pointer will swing drastically and the
discharge pressure is very high. In the both cases, stop the compressor at once, and if
technique is available, open the cylinder cover and check up the valve block, repair it,
or replace it with a new one,
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