Unit Operates Cool Mode Even If It Is Set To Heat Mode; Unit Operates Heat Mode Even If It Is Set To Cool Mode - Mitsubishi Electric MSC-A07WV Service Manual

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.
F F Check of R.V. coil

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

w First, measure the resistance of R.V. coil to confirm it is disconnected or is not short-circuit.
F F Check of R.V. coil
<MUH-A07/A09/A12WV>
Turn ON the power supply and operate
the indoor unit in HEAT mode by pressing
the EMERGENCY OPERATION switch.
After 3 minutes, does the unit
operate in COOL mode?
Is there 230V AC between
CN7211 – 2 on the deicer P.C.
board?
Replace the R.V. coil.
<MUH-A07/A09/A12WV>
Turn ON the power supply and operate
the indoor unit in COOL mode by pressing
the EMERGENCY OPERATION switch.
Yes
After 3 minutes, does the unit
operate in HEAT mode?
Yes
Is there 230V AC between
CN7211 – 2 on the deicer
P.C. board?
Yes
Replace the
deicer P.C. board.
No
OK
Yes
No
Replace the
deicer P.C. board
Yes
No
Ok
No
Replace the R.V. coil.
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