Carrier 40MFC - Indoor;Outdoor Units Communication Error Diagnosis and Solution (E1)

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2 --- Indoor / outdoor units’ communication error --- diagnosis and solution (E1)
Error Code E1
Malfunction conditions
Indoor unit does not receive feedback from outdoor unit in a 110 seconds period, and this condi-
tion occurs continuously four times.
Possible Causes
• Wiring connection mistake
• Defective Indoor or outdoor PCB
Trouble shooting:
Yes
Yes
Measure Vs, is it moving alternately
with positive value?
(Vs is the voltage between L2 and S
of outdoor unit. Connect the red pin of
multimeter with L2 port, and the black
pin with the S port
Yes
Power off, then turn on the unit 5 seconds
later(reconnect the power wire ).Is the error
still displaying after several minutes?
No
Replace the outdoor main PCB.
Power on. Is the error extinguished?
Check all the wiring with indoor units.
Is the wiring to the indoor main PCB
connected correctly?
Replace the indoor main PCB.
Yes
Replace the outdoor main PCB.
No
Check all the wiring with outdoor
u ni ts. Is th e wiring to the outdoo r
m ai n PCB con nect e d correctly? Is
the reactor connected well?
Power on. Is the error extinguished?
Replace the indoor main PCB.
No
Yes
Measure the resistance of the
reactor (the one without capacitor).
If it is zero , follow the step below. If
not, replace with a new reactor.
A14481
Notes:
• Make sure wires are connected per connection diagrams. Failing to do that will result in a communication error.
• Before measuring the Volts DC on outdoor TB, disconnect the field wire on terminal 1.
• Before measuring the Volts DC on Indoor TB, disconnect the field wire on terminal 1.
• Have the red probe of the meter on terminal L2 and the black probe on terminal S. Reconnect wiring when measurements a re
complete.
• When the system is running normally, the voltage will alternate between -50V to 50V.
• If the outdoor unit is malfunctioning, the voltage will move alternately with positive value. In the other hand, if the indoor unit is malfunction
ing, the voltage will have a specific voltage value.
Remark:
Use a multimeter to test the resistance of the reactor not connected to the capacitor.
The normal value should be around zero ohm. Otherwise, the reactor is defective and need to be replaced.