43
How to check miswiring and serial signal error
MUFZ-KJ25/35
M
• Turn OFF inverter-controlled lighting equipment.
• Turn OFF the power supply and then turn it ON again.
• Press EMERGENCY OPERATION switch.
A
Is serial signal
error indicated
6 minutes later?
B
Yes
• Reinstall either the unit or the
light away from each other.
• Attach a fi lter on remote
control receiving section of
the indoor unit.
No
Turn OFF the power supply.
Is there rated voltage in the
power supply?
Yes
No
Turn ON the power supply.
Check the power supply.
Is there rated voltage between
outdoor terminal block S1 and S2?
Yes
No
Check the wiring.
Press EMERGENCY OPERATION switch once.
Does the left lamp of OPERATION INDICATOR
lamp on the indoor unit light up? <Confi rmation
of the power supply to the indoor unit>
Yes
Correct the wiring.
Is the serial signal error
indicated 6 minutes later?
Yes
Is there any miswiring, poor contact or wire dis-
connection of the indoor/outdoor connecting wire?
No
Yes
No
A
Is there rated voltage between outdoor terminal block S1 and S2?
Yes
Check for miswiring, broken wires, and loose
wire connection between the power supply
and outdoor terminal block S1 and between
the power supply and outdoor terminal block
S2.
Wait for 2 or more minutes after the power supply is turned on.
Touch S2 and S3 with tester probes and start the emergency operation.
No
Turn the power supply ON.
When the emergency operation starts, does the rated voltage occur for 2
seconds between indoor terminal block S2 and S3?
Yes
Replace the indoor electronic
control P.C. board.
Does the left lamp of the OPERA-
TION INDICATOR lamp on the indoor
unit blink continuously 6 minutes af-
ter the emergency operation starts?
No
Does the outdoor LED light up?
Yes
Does the outdoor LED blink 6
times?
Yes
Confi rm that the thermostat is OFF
and wiring is not loose.
No
Does DC (6V or more) occur
between indoor terminal block S2
and S3?
Yes
Replace the outdoor inverter P.C. board. 1
No
Turn the power supply OFF.
Replace the indoor electronic
control P.C. board.
1.
Electric charge may remain immediately
after the power supply is turned OFF.
Perform the procedure after 3 minutes.
Replace the outdoor inverter P.C. board. 1
Yes
No
No
B
No
Was the indoor unit ever connected to
the Multi (MXZ) series and operated
(turned on)?
The connection information to the Multi series is
stored in the indoor unit. Refer to “Deleting the
memorized abnormal condition” described in 11-2.1
to clear the error history. When the error history is
being cleared, the connection information also will
be initialized. The indoor unit will be compatible with
a low-standby-power model after initialization.
OK
Yes
OBH668E
