Check code
4-way valve trouble in heating mode
Abnormal points and detection methods
Causes and checkpoints
If 4-way valve does not operate during heating operation.
When any of the following temperature conditions is satisfied for 3 min or
more during heating operation
1. TH22j−TH21j
[
−10°C [−18°F]
2. TH23j−TH21j
[
−10°C [−18°F]
3. TH22j
[
3°C [37.4°F]
4. TH23j
[
3°C [37.4°F]
Note:
For indoor unit, the abnormality is detected if an operating unit satisfies the
condition.
1. 4-way valve failure
2. Disconnection or failure of 4-way valve coil
3. Clogged drain pipe
4. Disconnection or loose connection of connectors
5.
Malfunction of input circuit on outdoor multi controller circuit board
6. Defective outdoor power circuit board
TH21: Indoor intake temperature thermistor (RT11 or TH1)
TH22: Indoor liquid pipe temperature thermistor (RT13 or TH2)
TH23: Indoor gas pipe temperature thermistor (TH-A to E)
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Diagnosis
Remedy
1508
(EF)
Yes
No
No
No
Yes
Yes
Is the connector for outdoor multi
controller circuit board or 4-way valve
coil disconnected or loose?
Reconnect the connector or connect it
tightly.
Disconnect the connector for outdoor multi
controller circuit board or 4-way valve coil
to check the resistance.
Replace the 4-way valve coil.
Replace the outdoor multi controller circuit
board.
Is the detected voltage normal?
Is it free from any trace of
over-heating or burning?
Is the resistance detected?
Check the voltage and appearance of the
outdoor multi controller circuit board.
Replace the 4-way valve.
61
OCH668G
Please refer to "8-5. HOW TO
CHECK THE PARTS" for ohm values.