Fujitsu AUXG36KRLB, Service Manual

Page: 69 / 169

2-14. E: 42. Indoor unit heat exchanger sensor error (Indoor
unit)
Indicator
Wired remote
controller
Error code E: 42
Detective actuator
Indoor unit main PCB
When heat exchanger temperature thermistor open or
short circuit is detected.
Heat exchanger temperature
thermistor
Forecast of cause
Connector connection failure
Thermistor failure
Main PCB failure
Check point 1. Check connection of connector
• Check if connector is loose or removed.
• Check erroneous connection.
• Check if thermistor cable is open
-> Reset power when reinstalling due to removed connector or incorrect wiring.
↓
Check point 2. Remove connector and check thermistor resistance value
• For the heat exchanger thermistor resistance value, refer to "Thermistor resis-
tance values" on page 03-62.
• If thermistor is either open or shorted, replace it and reset the power.
↓
Check point 3. Check voltage of main PCB
Make sure circuit diagram of each indoor unit and check terminal voltage at thermis-
tor (DC 5.0 V).
NOTE: For details of thermistor connector, refer to "Wiring diagrams" in Chapter 2.
TECHNICAL DATA AND PARTS LIST on page 02-24.
If the voltage does not appear, replace main PCB.
↓
End
2-14. E: 42. Indoor unit heat exchanger sensor error (Indoor unit)
- (03-19) -
2. Troubleshooting with error code
TROUBLESHOOTING TROUBLESHOOTING