Pioneer YN018GMFI16M2D Service Manual page 40

9.3.2.2 Voltage protection (ODU E5)
Voltage protection
Check the voltage of
outdoor unit power supply,
whether the voltage
between L(L1) and N (L2) is
about 220~240VAC
Yes
Check whether the voltage
of IPM board P and N is
normal? DC277-356V for
18-27KBtu/h; DC277-410V
for 36KBtu/h
No
Replace bridge rectifiers,
and then check whether the
system can run normally
No
Replace IPM board, and
then check whether the
system can run normally
No
Replace outdoor main board
No Check the power supply
Yes
Yes
Yes
Trouble is solved