Toshiba MMU-P0121H Service Manual page 82

Check code
[A6]
Discharge temperature TD1 alarm
In cooling
*
only model
In there blockage in
the check valve to interrupt
the liquid line?
NO
Replace the check valve
1. Outdoor unit service valve closed
2. Blockage of check valve to interrupt the liquid line.
3. Outdoor PMV A error or cooling bypass PMV B error
4. TD sensor error
5. Insufficient refrigerant, blockage in pipe
Are gas pipe,liquid pipe,
YES
and service valve of the
outdoor unit fully open?
YES
Is outdoor PMV A normal?
1. Connector connection
2. Wiring
3. Coil
4. Valve unit
5. Outdoor P.C. board
YES
YES
Is cooling bypass PMV B normal?
YES
Is resistance characteristics
of TD1 sensor normal?
YES
Is wiring correct?
YES
Insufficient refrigerant,
blockage, pipe breakage.
Operation cause
NO
NO
NO
NO
NO
Check miswiring of the outdoor unit
(
according to miswiring check function.
Check there is no blockage or pipe
(
breakage, and then addrefrigerant according
to judgment of refrigerant amount.
3-79
Open service valve fully.
Repair outdoor PMV A.
Cooling bypass PMV B error
Replace TD1 sensor.
Set normal wiring.
)
)