Carrier 619FB Service Manual page 22

TROUBLESHOOTING FOR MAIN MALFUNCTION
Indoor Unit
1. Malfunction of Temperature Sensor F1, F2
Troubleshooting for
F1,F2 malfunction
Is
the wiring terminal between the
temperature sensor and the controller
loosened or poorly contacted?
No
No
-
Is there a short circuit?
No
Is the
temperature sensor normal according
to the Resistance
Table?
Yes
Replace the mainboard
with the same model.
End
Yes
Insert the temperature
sensor tightly
Is malfunction
eliminated
Yes
Make sure all parts
fastened tight
Is malfunction
No
eliminated
No
Replace it with a
temperature sensor
with the same model
Is malfunction
No
removed
Yes
Fig. 25 – Troubleshooting
22
Yes
Yes