Check Of Defrost Heater (Base Pan Heater) - Mitsubishi Electric MUZ-GL09NA-U1 Service Manual

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 VAC 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?
Yes
The operation has stopped to pre-
vent 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 opera-
tion again to prevent
hazards.
OBH733D
NOTE: In case both thermistors are more than the above temperature, cool them with cold
water etc...
and
and (Other models)
No
Was the operation started with
the stop valve closed, and was
No
it opened during operation?
The refrigerant gas amount may be
60% or less than the normal amount.
Identify where the gas is leaking from,
and fi x the leak.
(MUZ-GL•NAH)
Yes
Not the problem of the inverter P.C. board.
Yes
No
59
The unit occasionally stops when the
stop valve is opened or closed during
operation. Open the stop valve and
start the cooling operation again.