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MCAC-PDSM-2013-04
1. Mechanical error
The mechanical error of compressor is mostly because that during the installation process it
is not strictly accorded to the operation guidelines, and the system refrigerant leakage and
improper trial run in the process of the construction and operation, and then cause the
compressor return liquid operation in long term.
Under such cases can lead to the compressor internal temperature over high, and
mechanical error including in the scroll badly worn, scroll jammed, and so on. For external
performance, the motor inside compressor resistance may be normal, but large noise will be
produced after the compressor start. When the error compressor starts, the pressure
difference between compressor suction and discharge ports is zero. If it is confirmed that
there are mechanical errors, then it must to replace the compressor.
2. Electrical error
The compressor electrical error mainly is that the compressor was burned and the wiring
terminals are blew out. Under this case, after power on the compressor, compressor still is
without any response. At this time, it should cut off the electricity, and then open the
compressor wiring box for visual inspection or using a multimeter to check the compressor
resistance. If there is any electrical error, it is necessary to change the compressor.
When compressor happens to completed burned, replace compressor and it also should be
replace drier-filter, and check the expansion valve. If there is any error, it also should be replaced.
Before the replacement, clean the system is necessary by right method. When changing the
compressor the skin must be avoided to directly contact with the refrigerant or lubricating oil,
otherwise it will cause severe frostbiting the skin, and it must wear protective gloves for handling
the contaminated components. After replace the compressor it must do serious analysis and
exclusion of the compressor error reasons, otherwise it may lead the new compressor to be
burned again.
1. Cut off the power supply.
2. Separate insert the suction pipe needle valve and discharge needle valve on the low
pressure and high pressure connectors of the pressure gauge, and to release the refrigerant.
3. Disconnect the electrical connection of the compressor.
4. Loosen the threading connectors in the suction pipe and discharge pipe of the compressor.
5. Remove the error compressor.
6. If the compressor was completely burned, it should clean the refrigeration system pipelines,
and replace the drier-filter and liquid sight glass.
7. Install the new compressor in place, and connect the pipeline connectors and electrical
circuit well.
8. According to the requirements of the debugging to vacuum the system and add refrigerant.
9. As the normal trial run to power on the system, check whether the system operation
parameters are normal. Through the liquid sight glass to observe the refrigerant status, and
combining with the system pressure and temperature parameters to confirm the adding
amount of refrigerant, until the system runs normally.
7.9 Outdoor fan maintenance
Check whether the fan operates normally, noisily, vibrates or blocks the bearing, etc.
Midea Precision AC Technical Manual-Down Delivery Series
87
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