Mitsubishi Electric MSZ-EF22VEW Service Manual page 27

D How to check miswiring and serial signal error
MUZ-EF Type
Is there rated voltage between outdoor terminal block S1 and S2?
Wait for 2 or more minutes after the main power supply is turned on.
Touch S2 and S3 with tester probes and start the emergency operation.
When the emergency operation starts, does the rated voltage occur for 2
seconds between indoor terminal block S2 and S3?
Yes
Does the indoor OPERATION
INDICATOR lamp (left) blink
continuously 6 minutes after the
emergency operation starts?
Yes
Does the outdoor LED blink 6
times?
Yes
Does DC (6V or more) occur
between indoor terminal block S2
and S3?
Yes
Turn the main power supply OFF.
Replace the indoor power P.C.
board.
Turn the main power supply ON.
Start the emergency operation.
Does the indoor OPERATION
INDICATOR lamp (left) blink
continuously 6 minutes after the
emergency operation starts?
Yes
Does DC (20V or more) occur
between indoor terminal block S2
and S3 ?
Yes
Replace the indoor electronic
control P.C. board.
Turn the main power supply
OFF.
Is there rated voltage in the power supply?
Yes
Check for incorrect indoor-outdoor connecting wiring.
A
B
Turn the main power supply ON.
Yes
No
Does the outdoor LED light up?
Confi rm that the thermostat is OFF
and wiring is not loose.
No
Replace the outdoor inverter P.C. board. 1
No
Replace the outdoor inverter P.C. board. 1
1.
Electric charge may remain immediately
after the main power supply is turned OFF.
Perform the procedure after 3 minutes.
No
Repair completed.
No
Replace the outdoor inverter P.C. board. 1
Check the power supply.
No
No
No
No
Yes
Wait for 2 or more minutes after the main power sup-
ply is turned ON. Touch CN202
probes and start the emergency operation.
27
Check for miswiring, broken wires, and loose
wire connection between the main power
supply and outdoor terminal block S1 and
between the main power supply and outdoor
terminal block S2.
Turn the main power supply
OFF.
Turn the main power supply
ON.
and JPG with tester
During the emergency operation,
does DC (2V or more) occur for 2
seconds between CN202 and
JPG on the indoor electronic control
P.C. board?
Yes
Replace the
indoor power P.C.
board.
A
• Turn OFF inverter-controlled lighting
equipment.
• Turn OFF the power supply and then
turn ON again.
• Press EMERGENCY OPERATION
switch.
• Reinstall
either the unit
or the light
away from
Is serial signal each other.
error indicated 6 • Attach a fi lter
No
on remote
minutes later?
control receiv-
Yes
ing section
of the indoor
unit.
B
No
Replace the
indoor electronic
control P.C. board.