Service manual

23
Check of R.V. coil
X
After 3 minutes, does the unit
operate in COOL mode?
Ok
Yes
Yes
No
Replace the
deicer P.C. board
No
Replace the R.V. coil.
Turn ON the power supply and operate
the indoor unit in HEAT mode by pressing
the EMERGENCY OPERATION switch.
Is there 220-240V AC
between CN7211 – 2 on the
deicer P.C. board?
Unit operates COOL mode even if it is set to HEAT mode.
w First, measure the resistance of R.V. coil to confirm it is disconnected or is not short-circuit.
<MUH-07/09/12RV>
Check of outdoor thermistor
Measure
resistance
between CN 661
1 and 2.
No
Yes
Replace the
thermistor.
Defrost thermistor (RT61)
Re-connect CN661.
Turn ON the power
supply and press
the EMERGENCY
OPERATION
switch.
Does the resistance
of thermistor have
the characteristics ?
No
Yes
Does the unit operate
10 minutes or more?
Replace the deicer P.C.
board.
Ok ❈
❈ Defective contact of the connector is considered.
Turn OFF the
power supply.
Start
W
When OPERATION INDICATOR lamp flashes 6-time.
Thermistors in the outdoor unit are abnormal.
<MUH-07/09/12RV>
OB252C-1.qxp 02.4.25 11:27 AM Page 23