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Check the frost on the cabinet liner surface, if find like following:
1) No frost, then do the leakage detecting.
A). If the leakage point is found, then first cut off the low pressure pipe to discharge the left
refrigerant in the system, then clean the pipe, replace with a new dry filter and welding again,
again recharge the refrigerant and do the leakage detecting.
B). If the leakage can not be found, cut off the low pressure pipe, if there is no refrigerant
omitting, then recharge the refrigerant and do the leakage detecting again; If there is refrigerant
omitting, cut off the high pressure pipe(means that compressor suction is normal), charge the
condenser pipe with pressurized nitrogen, if no air at low pressure side, means the pipe is
blocked, then replace the blocked parts and clean the system pipe; If no air suction at compressor
low pressure side, cut off the high pressure pipe, means air compression of the compressor is not
good, please replace the compressor.
2). A little frost on the surface, also do the leakage detecting first.
A) If the leakage point is confirmed, then cut off the low pressure pipe, if a little
refrigerant air spurt out, means that the system leaks slowly on the leakage point, you should
repair the welding of cut pipe and the leakage point and clean the system pipe by the high
pressure nitrogen, replace the dry filter, after completion these work, re-vacuum and recharge the
refrigerant, at last do the leakage detecting again.
B). If big quantity refrigerant spurt out, cut off the high pressure pipe to check the suction of
the compressor low pressure pipe is normal or not: if no suction or weak suction, it means not
good compression and need to replace the compressor; if normal suction, then charge the clean
and warm nitrogen to the condenser pipe, if you find the returned nitrogen of the low pressure
side is not sufficient, it means that the system pipe is clogged lightly, please replace the clogged
parts and clean the pipe.
3). No frost, but have condensate water on the surface on the cabinet liner, check the temperature
of the high pressure side pipe and the compressor, you will find it is too high temperature and
check the low pressure pipe with frost, if like this, means too more refrigerant in the system,
please recharge with appropriate quantity refrigerant once more.
4) The unit works discontinuously, maybe the system is clogged with ice, please replace the dry
filter and clean the system with clean and warm nitrogen.
5) Compressor doesn’t run.
Please check the electrical parts, such as PTC starter, capacitor, overload protector, thermostat
etc., if you find the parts go wrong, then replace a new one with same type and specification. If
all of these parts are good, please measure the resistance of the compressor winding, if the
resistance is abnormal, must replace the compressor; otherwise check the overload protector act
or not, means the over large current and compressor goes wrong, also replace the compressor.
