Midea MSC-21CRN1, Service Manual

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Service manual
37
PROBLEM CAUSE REMEDY
Temperature sensor
failure
Replace after checked failure.
Connector failure or loose Repair or replace the sensor.
Outdoor PCB failure
Replace after checked failure.
Temperature sensor
failure
Replace after checked failure.
Connector failure or loose Repair or replace the sensor.
Indoor PCB failure
Replace after checked failure.
Soft starter module failure
Check the module and the capacitor connected to the
module. Replace if failure.
Power failure Wait if checked the power voltage is really too low.
Wiring failure Correct if indoor fan motor wiring is loose.
Indoor fan motor failure Check the input of fan motor. Replace if failure.
Indoor PCB failure Replace after checked failure.
Zero-crossing
error
Indoor PCB failure Replace after checked failure.
Air filter Clean or replace if restricted.
Unit undersized
Determine if the unit is properly sized for the area to be
cooled or heated.
Condenser and
Evaporator
Clean or replace if restricted.
Room structure
Take proper measures to make the door and windows
sealed well if gap is found.
Air flow
Clean or remove if any barrier is found to block the
inlet/outlet wind flow of the unit.
Sunlight Add a awning if the outdoor unit is exposed to the sunlight.
Outdoor fan motor
Check the fan capacitor on outdoor power control board and
replace the board if not /-10% of manufacturer's
rating. Replace the motor if the speed is not /-10% of
manufacturer's rating but not because of the capacitor.
For electrical function 2.3 models. Check the fan capacitor in
indoor electric box (for some models, the capacitor is on
main PCB.) and replace the capacitor (or main PCB) if not
/-10% of manufacturer's rating.
Replace the motor if the speed is not /-10% of
manufacturer's rating but not because of the capacitor.
Less refrigerant
Check the tubes for reasons of leakage. Recycle the
refrigerant, correct the leakage points and recharge.
Capillary tube
Regulate the flow if capillary tube is blocked. Make the
evaporating temperature appropriate if the evaporator is
frosted.
Compressor
The inlet and outlet valve of the compressor is damaged,
making the low pressure connected with the high pressure.
The refrigerating system is difficult to produce high pressure
and low pressure. Replace the compressor after checking for
the reason.
Heat sources Reduce if over loaded.
reverse valve
The two paths for refrigerant are connected, making the low
pressure connected with the high pressure. The refrigerating
system is difficult to produce high pressure and low
pressure. Replace the reverse valve after checking for the
reason
Insufficient
cooling or
heating.
indoor fan motor
Open or short
circuit of outdoor
temperature
sensor
Room temp or
evap temp sensor
open or short
circuit
Over load or too
low voltage
protection
Fan speed
beyond control