Lennox LI018CI-180P432 Service Manual page 54

Service Manual
5. Diagnosis for compressor synchronism (AP1 below is control board of outdoor unit)
Main detection point:
● If the system pressure is over-high?
● If the work voltage is over-low?
Malfunction diagnosis process:
Synchronism after
N
compressor is more than
If the compressor wire COMP(UVW) is well
connected, the connection sequence
forwards to clockwise direction?
N
Connect
wire well
Y
Installation and Maintenance
energize the unit
and start it
If the stop time of
3min
Y
Y
Replace
control board
AP1
Remove
malfunction?
N
Replace
compressor
End
Synchronism
occurred during
operation
If the outdoor fan works
N
normally?
Y
If the radiating of unit is
Y
well?
N
If the input voltage of unit
N
is normal?
Y
If the refrigerant is too
Y
much?
N
Replace
control board
AP1
Remove
malfunction?
Y
N
Replace
compressor
End
Check if the fan
Replace fan
terminal OFAN is
capacitor C1
connected well
Replace
Improve the radiating
outdoor fan
of unit (clean heat
exchanger and
increase ventilation)
Start to run until the
power resume normal
voltage
Charge the
refrigerant with
service manual
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