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10.2 Error Code: EL 01 (Indoor and outdoor unit communication error diagnosis and solution)
Description: Indoor unit can not communicate with outdoor unit
Recommended parts to prepare:
•
Indoor PCB
•
Outdoor PCB
•
Short-circuited component
Troubleshooting and repair:
Does the error
code disappear?
Power off, then restart the unit after
2 minutes.
Measure the DC voltage between N/L2
and S (Black pin to N/L2, Red pin to S).
The value is fixed
and close to 0.
The value is alternative
from negative to positive.
The value is
always positive
Check the
wiring connection
between indoor and
outdoor unit, are
they good?
Check the wiring connection from
the outdoor terminal to outdoor
PCB and wiring between PCBs if
there is more than 1 PCB.
Check the wiring connection
from indoor terminal to
indoor PCB, are they good?
Turn on the
unit, check if W and 1(L)
are connected?
Is the power
LED is on?
YES
YES
YES
Unplug all the high voltage
components connected to the main PCB
such as a 4-way valve, heater, AC fan
one by one to check their resistance.
Is there any component short circuit?
Unplug electronic expansion valve.
Is power LED is on?
NO
NO
Check the AC voltage of L, N
output to IPM board, is it the
same as the power input?
Check the DC 5V, 12V from IPM
board to main PCB, are they normal?
Unplug all the high voltage components
connected to the main PCB such as a
4-way valve, heater, AC fan one by one
to check their resistance. Is there any
component short circuit?
YES
NO
Unplug electronic expansion valve.
Check if the DC 5V, 12V to main
PCB are OK.
Replace
short-circuited
component and
main PCB.
Replace coil
of electronic
expansion valve.
Replace
outdoor PCB
YES
YES
YES
YES
Replace
main PCB
NO
YES
NO
Replace IPM board
NO
Replace indoor
PCB
Solved
Correct the connection
or change wires
NO
NO
YES
For units with both a main PCB and IPM board
For units with only one PCB
For units with W wire
For units without W wire
NO
Replace
short-circuited
component and
outdoor PCB.
NO
Note: For certain models, outdoor PCB
could not be removed separately. In this
case, the outdoor electric control box
should be replaced as a whole.
****Disclaimer****
The error codes and descriptions are for reference only. If your system displays any of
these codes contact a qualified technician to investigate the matter further.
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