Service Manual

8.4.1.7 Over voltage or too low voltage protection diagnosis and solution.

Voltage protection

Check the voltage of

outdoor unit power supply,

whether the voltage

between L(L1) and N (L2) is

about 187~253VAC

Check the power supply

Check whether the voltage

of IPM board P and N is

normal? DC277-356V for

18-27KBtu/h; DC277-410V

for 36KBtu/h

Replace bridge rectifiers,

and then check whether the

system can run

normally(Only for qua-

zone)

Replace IPM board, and

then check whether the

system can run normally

Replace outdoor main board

Yes

Trouble is solved

Yes