Fujitsu ABHG18KRTA, Service Manual

Page: 265 / 471

2-33. E: 77. Heat sink thermistor error (Outdoor unit)
Indicator Indoor unit
Operation indicator 7 time flash
Timer indicator 7 time flash
Economy indicator Continuous flash
Error code E: 77
Detective actuator Heat sink temperature thermistor Heat sink temperature thermistor short or open detected
Forecast of cause
Connector failure
Thermistor failure
Inverter 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 sink thermistor resistance value, refer to "Thermistor resistance val-
ues" on page 03-94.
• If thermistor is either open or shorted, replace it and reset the power.
↓
Check point 3. Check voltage of inverter PCB
Make sure circuit diagram of outdoor unit and check terminal voltage at thermistor
(DC 5.0 V).
NOTE: For details of thermistor connector, refer to "Wiring diagrams" in Chapter 2.
TECHNICAL DATA AND PARTS LIST on page 02-117.
If the voltage does not appear, replace inverter PCB.
↓
End
2-33. E: 77. Heat sink thermistor error (Outdoor unit)
- (03-49) -
2. Troubleshooting with error code
TROUBLESHOOTING TROUBLESHOOTING