Four Way Valve Abnormality - Daikin FTX-N Series Service Manual

Troubleshooting for Outdoor Unit
7.6

Four Way Valve Abnormality

EA
Error Code
Method of Error
The room temperature thermistor and the indoor heat exchanger thermistor are checked if they
Detection function within their normal ranges in each operation mode.
Error Decision The following condition continues over C seconds after operating for 5 minutes.
Conditions  Cooling/Dry
 Heating
Outdoor temperature
–15°C (5°F) or higher
Lower than –15°C (5°F)
 If the error repeats, the system is shut down.
 Reset condition: Continuous run for about 60 minutes without any other error
Supposed
 Disconnection of four way valve coil
Causes  Defective four way valve, coil, or harness
 Defective outdoor unit PCB
 Defective thermistor(s)
 Refrigerant shortage
 Water mixed in refrigerant
 Defective stop valve
161
A – B < –5°C (A – B < –9°F)
B – A < –5°C (B – A < –9°F)
A: Room thermistor temperature
B: Indoor heat exchanger temperature
09 class
C (seconds)
12 class 15 class
300 300 300
600 300 1400
SiUS091601EA
18 class 24 class
300 300
1400 1400
Part 6 Service Diagnosis