Service manual

Check of indoor electronic control P.C. board

The unit doesn’t operate with the remote controller.

Also, the OPERATION INDICATOR lamp doesn’t light up by pressing the EMERGENCY OPERATION switch.

Replace the fuse.

Replace the indoor electronic

control P.C. board.

Replace the varistor.

Yes

Is varistor(NR11)burnt?

Yes

Is fuse(F11)blown?

Check of outdoor unit

<MUCFH-18TN - >

Start

Press EMERGENCY OPERATION

switch. 3-minute time delay works.

Test run operation operates for 30

minutes.

Check the outdoor DEICER P.C.board and

compressor contactor at first, then check the

outdoor fan motor and compressor.

Check the continuity of indoor and outdoor

unit connection.

Yes

Check voltage to terminal

block of indoor unit. Is

there 220V AC to terminal

block between 2 - N ?

Check voltage to terminal

block of outdoor unit. Is

there 220V AC to termi-

nal block between 2 - N

Be sure to check both fuse

and varistor in any case.

Replace the indoor electronic control

P.C.board.

Check both “parts side” and

“pattern side” of indoor

electronic control P.C. board

visually.

Compressor and / or outdoor fan motor does not operate.

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