The Other Cases - Mitsubishi Electric MSC-07RV Service Manual

Check of mis-wiring or mis-piping
T
Checking the mis-wiring and serial signal error (Only MXZ-32RV)
<The outdoor unit does not operate.>
Single or repeated blinks appears on the operation indicator (on the left-hand side).
Using the light emitting diode LED1 on the indoor controller board (See the indoor unit service manual) ,
locate the defect in the following procedure.
After checking the indoor unit, check the outdoor unit as follows. For the
indoor unit inspection, refer to the appropriate service manual.
Measure the voltage between the appropriate connector
terminals on the outdoor controller board depending on
the indoor unit indicating the serial signal error.
• When the indoor unit for Room A is indicating the
serial signal error : Is there voltage of 5 to 10 V DC
between pin 1 (+) and pin 2 (-) at connector CN601?
• When the indoor unit for Room B is indicating the
serial signal error : Is there voltage of 5 to 10 DC
between pin 1 (+) and pin 2 (-) at connector CN602?
• When the indoor unit for Room C is indicating the
serial signal error : Is there voltage of 5 to 10 DC
between pin 1 (+) and pin 2 (-) at connector CN603?
• When the indoor unit for Room D is indicating the
serial signal error : Is there voltage of 5 to 10 DC
between pin 1 (+) and pin 2 (-) at connector CN604?
Yes
Outdoor controller board

The other cases

U
In the case that the indoor fan and outdoor fan operate but the compressor does not operate,it causes that the high
pressure switch can be operated once.
First of all,check the high pressure switch can be shorted, turn OFF the power and turn ON again 1 minute later.
<Only MXZ-32RV>
No
Check the indoor/outdoor con-
necting wire, the unit signal 1
wire, and the outdoor terminal
block.
• Reactor
• Diode stack
• Power factor capacitor
• Smoothing capacitor
• Rush current control circuit
• IPM board
<MXZ-18/32RV>
Disconnect the short circuit between tab
Yes
terminals as before. Is the LED1 lighting on
the outdoor controller board?
Yes
}
faulty
141
No lighting
Is there 12 V DC between pin
1 and pin 2 at connector
CN801 on the outdoor con-
troller board?
No