M-Series MUZ-GE Technical & Service Manual

ManualsBrandsMitsubishi ManualsCoolingM-Series - 15,000 BTU - Ductless Heat Pump System - Wall Mounted - 21.6 SEER - 11.2 HSPF

Is the resistance of thermistor normal? (Refer to 10-6.1.)

Reconnect the connector of thermistor.

Turn ON the power supply and press EMERGENCY OPERATION switch.

Replace the thermistor except RT64. When RT64 is

abnormal, replace the inverter P.C. board.

Does the unit operate for 10 minutes or more

without showing thermistor abnormality?

OK (Cause is poor contact.)

Replace the inverter P.C. board.

Thermistor Symbol Connector, Pin No. Board

Defrost (MUZ) RT61 Between CN641 pin1 and pin2

Inverter P.C. board

Discharge temperature RT62 Between CN641 pin3 and pin4

Fin temperature RT64 Between CN642 pin1 and pin2

Ambient temperature RT65 Between CN643 pin1 and pin2

Outdoor heat exchanger temperature RT68 Between CN644 pin1 and pin3

Yes

G Check of outdoor thermistors

H Check of R.V. coil

Disconnect the connector of thermistor in the inverter P.C. board (see

below table), and measure the resistance of thermistor.

MUZ-GE09/12/15NA/NA2/NAH/NAH2, MUZ-GE18NA/NAH, MUZ-GE24NA

First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to 10-4.

In case CN721 (MUZ-GE09/12/15/18)/CN602 (MUZ-GE24) is disconnected or R.V. coil is open, voltage is generated

between the terminal pins of the connector although no signal is being transmitted to R.V. coil. Check if CN721 (MUZ-

GE09/12/15/18)/CN602 (MUZ-GE24) is connected.

Is there 208/230 VAC between CN721 (MUZ-

GE09/12/15/18)/CN602 (MUZ-GE24)

and

on the inverter P.C. board 3 minutes after the

power supply is turned ON?

Yes

Replace the inverter

P.C. board.

Replace the 4-way valve.

Unit operates COOL mode even if it is set to HEAT mode.

Disconnect connector between the

compressor and intelligent power module/

power module

Turn ON the power supply and press

EMERGENCY OPERATION switch twice

(HEAT mode).

MUZ-GE09/12/15NA/NA2/NAH/NAH2, MUZ-GE18NA/NAH, MUY-GE09/12/15NA/NA2, MUY-GE18NA

Thermistor Symbol Connector, Pin No. Board

Defrost (MUZ) RT61 Between CN671 pin1 and pin2

Inverter P.C. board

Discharge temperature RT62 Between CN671 pin3 and pin4

Fin temperature RT64 Between CN673 pin1 and pin2

Ambient temperature RT65 Between CN672 pin1 and pin2

Outdoor heat exchanger temperature RT68 Between CN671 pin5 and pin6

MUZ-GE24NA, MUY-GE24NA

Intelligent power module: MUZ-GE09/12/15/18/24NA, MUY-GE09/12/15/18/24NA

Power module: Other models

OBH549G