E1 (Indoor And Outdoor Unit Communication Error) - Carrier 42QHP09E8S Service Manual

5.3

E1 (Indoor and outdoor unit communication error)

Description: The indoor unit has not received feedback from the outdoor unit for 150 seconds, four consecutive times.
Recommended parts to prepare:
• Indoor PCB
• Outdoor PCB
• Reactor
Troubleshooting and repair:
Power off, then restart the unit after 2 minutes.
Measure Vs. (Vs is the voltage between S and N of
outdoor unit. Red pan-S, Black pan-N)
Check the outdoor wiring connection.
Replace the
reactor
 Page 62 
Does a problem remain?
YES
Is the voltage moving
alternately between Positive and
negative?
NO
The voltage moves alternately with
positive value.
Is it normal?
YES
Check the reactor.
NO Is it normal?
YES
Replace the outdoor PCB.
Power on.
Is the error
resolved?
NO
Replace the indoor PCB.
NO The unit is operating normally
The voltage is a
NO
certain value
Check the indoor wiring
connections
Is it normal?
YES
Replace the indoor PCB.
Power on.
Is the error resolved?
NO
Replace the outdoor PCB.