Mitsubishi Electric MUZ-GL12NA Service Manual page 59

N Check of defrost heater (base pan heater)
MUZ-GL09/12/15/18/24NAH
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?
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.
Is there 208/230 V AC between CN601
(MUZ-GL24NAH)/CN722
on the inverter P.C. board? Refer to 10-6.1.
Replace the inverter P.C. board.
O Check of outdoor refrigerant circuit
Has the operation stopped during pump down?
No
Was the operation started with the stop valve
closed, and was it opened during operation?
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.
OBH733J
NOTE: In case both thermistors are more than the above temperature, cool them with cold
water etc...
and
and (Other models)
No
Yes
Yes
(MUZ-GL•NAH)
Not the problem of the inverter P.C. board.
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.
CAUTION :
Do not start the operation again to prevent hazards.
The unit occasionally stops when the stop valve is opened
or closed during operation. Open the stop valve and start the
cooling operation again.
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