Carrier 38MGRBQ18B-3 Service Manual page 40

38MGRBQ: Service Manual
DIAGNOSIS AND SOLUTION (CONT)
Temperature sensor malfunction diagnosis and solution
ERROR CODE
MALFUNCTION DECISION
CONDITIONS
SUPPOSED CAUSES
Troubleshooting
Check the resistance value
of the sensor via Appendix 1
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
E4, EC 53, EC 54, EC 56 OR EC 50
If the sampling voltage is lower than 0.06V or higher than 4.94V, the LED displays a failure.
PCB faulty
Sensor faulty
Wiring mistake
Check the connections
between the temperature
sensor and PCB. Are
the connections good?
Yes
and Appendix 2
Is it normal?
No
Replace the sensor
No Correct the connections.
Yes Replace indoor or outdoor PCB.
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