Toshiba HFC R407C Service Manual page 60

Diagnostic procedure for check code
Check code
[AE]
Low pressure fault (Ps)
Detected by low pressure switch <0.02 MPa
Is Ps switch connector
correctly connected?
Yes
Is Ps switch normally closed (NC)?
Yes
Is low pressure below
0.95 MPa during
operation of compressor?
Yes
Check interface PC board.
Check code
[AF]
Outdoor unit power source phase
order miswiring
There is an abnormal power phase order or missing phase of power supply to the outdoor unit. Check
power supply wiring.
60
Troubleshooting
Operation cause
1. Ps pressure switch error.
2. Ps switch connection error.
3. Compressor compressing error.
4. 4-way valve error.
5. Refrigeration undercharge.
6. Gas leak.
No
No
Does refrigerant bypass
No
from outlet to inlet on 4-way
valve?
Yes
Check 4-way valve.
Operation cause
Abnormal power phase order or missing phase of
power supply to the outdoor unit.
Modify connector connection.
PJ9 (MCC-1223)
Ps switch error.
Replace switch.
Check compressor.
No
Confirm refrigeration charge correct.
(No leaks from system.)