Carrier 38QUA009DS, Service Manual, Page: 95 / 116

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16.3.2 Communication malfunction between indoor and outdoor units diagnosis and solution
(E1)
For 18K-24K:
Error Code E1
Malfunction conditions If the indoor unit does not receive feedback from outdoor unit for
110 seconds 4 consecutive times.
Potential causes
●
Wiring mistake
●
Faulty indoor or outdoor PCB
Trouble shooting:
Measure Vs, is it positive fluctuation?
(Vs is the voltage between 3 and 2 of
outdoor unit. Red pan-3, Black pan-2)
Measure Vs, is it positive fluctuation?
(Vs is the voltage between 3 and 2 of
outdoor unit. Red pan-3, Black pan-2)
Yes
Power off, then restart the unit 2 minutes later
Power off, then restart the unit 2 minutes later
No
Replace the outdoor main PCB.
Power on. Is the error
extinguished?
Replace the outdoor main PCB.
Power on. Is the error
extinguished?
Check the outdoor wiring connection
Check the outdoor wiring connection
Replace the indoor main PCB.
Power on. Is the error
extinguished?
Replace the indoor main PCB.
Power on. Is the error
extinguished?
Yes
Replace the outdoor main PCB.
Replace the outdoor main PCB.
No
Replace the indoor main PCB.
Replace the indoor main PCB.
No
Check the indoor wiring connection
Check the indoor wiring connection
Yes
Yes
Check whether reactor
is normal?
Check whether reactor
is normal?
Yes
Replace the reactor
Replace the reactor No