39
N Check of defrost heater
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 VAC between CN722 and
(
MUFZ-KJ09/12
)/CN601 and (
MUFZ-
KJ15/18
) 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...
MUFZ-KJ09NAHZ MUFZ-KJ12NAHZ MUFZ-KJ15NAHZ MUFZ-KJ18NAHZ
Has the operation stopped
during pump down?
Was the operation started with
the stop valve closed, and was
it opened during operation?
No
Yes
O Check of outdoor refrigerant circuit
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.
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
fi
x the leak.
CAUTION : Do not start the opera-
tion again to prevent
hazards.
OBH753A
