Mitsubishi Electric MXZ-2B20NA Service Manual page 30

• When the operation frequency does not go up from the lowest frequency.
The other cases
Indoor unit does not operate. (different operating models in multi system)
• When you try to run two indoor units simultaneously, one for cooling and the other for heating, the unit which
transmits signal to the outdoor units first decides the operation mode.
• When the above situation occurs, set all the indoor units to the same mode, turn OFF the indoor units, and
then turn them back ON.
• Though the top of the indoor unit sometimes gets warm, this does not mean malfunction. The reason is that
the refrigerant gas continuously flows into the indoor unit even while it is not operating.
Check of bus-bar voltage
Blink 5 times
Replace the power board.
Turn ON power supply. Start
operation.
Confi rm LED1 indication lamp
on the outdoor electronic con-
trol P.C. board.
Blink 9 times
Replace the outdoor elec-
tronic control P.C. board.
Turn OFF power supply before removing P.C. board.
•Check the voltage of power supply.
•Confi rm outdoor unit failure mode
recall function. (Refer to 11-2.2.)
Confi rm LED1 indication lamp on
the outdoor electronic control P.C.
board.
Blink 6 times
Replace the outdoor elec-
tronic control P.C. board.
Normal
Lighting
Replace the outdoor elec-
tronic control P.C. board.
Turn ON power supply. Start
operation.
Confi rm LED1 indication lamp
on the outdoor electronic con-
Lighting
trol P.C. board.
Replace the power board.
30
Lighting
Blink 9 times