Lennox LICH4012021T431E-1, Service Manual

Page: 143 / 164

Troubleshooting
Electrical Control System
141
2.4.4.10. P1 malfunction
Malfunction decision
conditions
An abnormal voltage rise or drop is detected by checking the
specified voltage detection circuit.
Supposed causes ⚫
Abnormal p
ower supply
⚫
Wiring
mistake
⚫
Faulty
bridge rectifier
⚫
Faulty IPM
board
Voltage protection
Voltage protection
P1 display
P1 display
Check whether the power
voltage is normal.
Check whether the power
voltage is normal.
Measure whether outdoor
terminal voltage is normal
？
Measure whether outdoor
terminal voltage is normal
？
Restart the unit when the power
supply gets normal
Restart the unit when the power
supply gets normal
No
Yes
No
Reconnect it well
Reconnect it well
Yes
Yes
No
Replace the IPM board, If the IPM board
and main board is in a board, replace the
outdoor main PCB
Replace the IPM board, If the IPM board
and main board is in a board, replace the
outdoor main PCB
Yes
Replace the PFC module(If has)
Replace the PFC module(If has)
No
Yes
Measure whether the voltage
between L and N is normal
？
Measure whether the voltage
between L and N is normal
？
Yes
Measure whether input voltage
of bridge rectifier is normal
？
Measure whether input voltage
of bridge rectifier is normal
？
Yes
No
No
Measure whether the voltage
between P and N is normal
refer to the Appendix 3
？
Measure whether the voltage
between P and N is normal
refer to the Appendix 3
？
Replace the bridge
rectifier
Replace the bridge
rectifier
No
Check whether
bridge rectifier is
normal
Check whether
bridge rectifier is
normal
Check the wiring of
reactor or inductance
Check the wiring of
reactor or inductance
Reconnect the
wiring
Reconnect the
wiring
No
Check whether reactor
or inductance is normal
Check whether reactor
or inductance is normal
Yes
Replace reactor or
inductance
Replace reactor or
inductance
No
Check the wiring of
power wires well or
correctly
Check the wiring of
power wires well or
correctly
Reconnect it well
Reconnect it well
Check the wiring of
L and N well or
correctly
Check the wiring of
L and N well or
correctly
Reconnect it well
Reconnect it well
Check the wiring of
bridge rectifier well
or correctly
Check the wiring of
bridge rectifier well
or correctly