Mitsubishi Electric MXZ-2A30VA - E1 Service Manual page 137

• When the operation frequency does not go up from lowest frequency.
Check of HPS
MXZ-4A80VA/5A100VA
1. Disconnect the connector CN681 in the electronic control P.C. board.
2. Check the resistance of HPS 1 minute after the outdoor unit power supply was turned OFF.
Check the resistance between
each terminal.
0Ω
Reconnect CN681.
Turn ON the power supply to the indoor and outdoor unit.
3 minutes later, start EMERGENCY OPERATION.
Is HPS protection displayed
immediately after compressor
starts?
No
Normal
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 unit first decides the operation mode.
• When the above situation occurs, set all the indoor units to the same mode, turn OFF the indoor units, 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
MXZ-3A/4A/5A
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.
Infinity
Replace HPS.
Yes
Replace the electronic control P.C. board.
•Check the voltage of power supply.
•Confi rm outdoor unit failure mode
recall function. (Refer to 13-2.2.)
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.
137
Lighting
Blink 9 times