Lennox MPA009S4S Service Manual page 143

Error Code:
P0
Description: IPM module or IGBT over current protection.
General Note: When the voltage signal that IPM sends to the compressor drive chip is abnormal, the display LED will show "P6" and unit
will turn off.
P6
Check whether the voltage range
of P-N on IPM module is normal?
277-356VDC for 18-30KBtu/h; 277-
410VDC for 36KBtu/h
Yes
Check whether the connecting wiring
between main board and the IPM
module is connected tightly.
Check whether the connecting wiring
to the compressor is connected cor-
rectly and tightly
Replace the IPM
module, check
whether the system
works normally.
Check if the outdoor
fan runs properly
or the outdoor unit
ventilation is good.
Replace the main board;
check whether the system
operates normally?
Yes
Replace the compressor,
check whether the system
operates normally?
Connect it tightly,
No
unit operates
Yes
No
Connect it tightly,
check ok or not?
Yes
No
No
For AC fan models,
check whether the resis-
tance of the fan motor
is normal. If not, replace
Yes
the fan motor. For DC
fan models, refer to the
solution of fan speed
malfunction (E8) . Find
No
out the cause and repair
it.
Yes
No
Yes
Check whether
the input power
No
supply is cor-
rect? 208-230V,
1PH, 60Hz
Check whether the
power supply line
is connected cor-
correctly?
rectly and tightly.
Check whether
the lines in E-
part box are con-
nected tightly.
Check whether the bridge rectifiers
are normal? Use the multimeter to
measure the resistance between
each two terminals, check whether
there is the condition that value of
Yes
Problem Solved
143
Correct the incom-
ing power problem,
then check whether
No
the system operates
normally
No
Yes
Connect it correctly
No
and tightly, check
ok or not?
Yes No
No
Connect it tightly,
check ok or not?
Yes No
resistance is 0.
Yes
Check whether the wiring
of each reactor is correct?
Replace the wiring
or reactor or replace
the PFC module
No
Replace the
bridge rectifiers.
No