Mitsubishi Electric MSY-GL-NA Series, Service Manual

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59
O Check of outdoor refrigerant circuit
N Check of defrost heater (base pan heater)
MUZ-GL09/12/15/18/24NAH
(MUZ-GL • NAH)
Check the following points before checking electric continuity.
1. Does the resistance of ambient temperature thermistor have the characteristics? Refer to 10-6.1.
2. Is the resistance of defrost heater normal? Refer to 10-4.
3. Does the heater protector remain conducted (not open)?
4. Are both ambient temperature thermistor and circuit of defrost heater securely connected to connectors?
Is there 208/230 V AC between CN601 and
( MUZ-GL24NAH )/CN722 and ( Other models )
on the inverter P.C. board? Refer to 10-6.1.
Not the problem of the inverter P.C. board.
Replace the inverter P.C. board.
No
Yes
In HEAT mode, for more than 5 minutes, let the ambient temperature thermistor continue to read
32°F (0°C) or below, and let the defrost thermistor continue to read 30°F (-1°C) or below.
NOTE: In case both thermistors are more than the above temperature, cool them with cold
water etc...
Has the operation stopped during pump down?
Was the operation started with the stop valve
closed, and was it opened during operation?
No
Yes
The operation has stopped to prevent the diesel explosion
caused by air trapped in the refrigerant circuit. Close the stop
valve, and disconnect the power plug or turn the breaker OFF.
The unit occasionally stops when the stop valve is opened
or closed during operation. Open the stop valve and start the
cooling operation again.
Yes
No
The refrigerant gas amount may be 60% or less than
the normal amount. Identify where the gas is leaking
from, and fix the leak.
CAUTION :
Do not start the operation again to prevent hazards.
OBH733J