Toshiba HFC R407C Service Manual page 46

Diagnostic procedure for check code
Check code
[21]
Inverter high pressure SW system alarm
Does the inverter high pressure
switch operate?
Yes
Are the inverter high pressure
switch parts normal?
Yes
Is service valve fully open?
Yes
Does the cooling outdoor fan
normally operate?
Yes
Is there a problem with the
outdoor unit heat exchanger?
(1) Blockage of heat exchanger
(2) Short circuit
No
Il circuito di bypass della SV2 è normale?
Is SV2 bypass circuit normal?
Yes
A
46
Troubleshooting
No
No
Check parts.
If defective, replace.
No
Open service valve fully.
No
Are the connection, capacitor
and fan motor normal?
Are the high pressure sensor
Yes
characteristics normal?
Remove cause.
No
(Coil error, disconnection of wiring, etc.)
Repair SV2 bypass circuit.
Operation cause
1. Inverter high pressure SW error.
2. Inverter IOL operation.
3. Service valve closed.
4. Outdoor fan, capacitor error.
5. Indoor/Outdoor PMV blockage.
6. Outdoor heat exchanger blockage.
7. SV2 circuit blockage.
8. Indoor – Outdoor communication error.
9. Pd sensor error.
10.Refrigerant overcharge.
See judgment flow of IPDU IOL
operation circuit "E5".
Check and modify wiring
No
Yes
Repair defective position.
No
Yes
Replace high pressure sensor.
Check outdoor IPDU PC board.
If defective, replace board.
No
Is the inverter IOL
circuit normal?
Yes
No
Is circuit wiring normal?
Yes