7. Module protection :
Handling method:
Check if the voltage between power module P and N is too low and
if the current is too high. In normal condition, voltage between P and
N should be about 320V.
Normal
Abnormal
Check power supply circuit of outdoor unit (if PTC resistance
rectifying bridge, reactor, capacitance etc. is ok).
Temperature of power module is too high,
which causes overheating protection
Protection is still displayed
Confirm the setting status of outdoor unit (cooling)
Normal
Confirm if outdoor fan motor is running; unplug the
three connecting wires between U, V, W of compressor
and power module. Turn on the unit to see if outdoor
fan runs normally (about 1 minute)
Outdoor fan stops
Measure the voltage of outdoor
fan connector
No voltage
Normal voltage
Replace the fan
Replace the mainboard
motor
of outdoor unit
Check if radiating paste is spread
evenly or radiating sticker is stuck
well; if screws of power module
is tightened
Reinstall power module and
re-spread radiating paste or
stick radiating sticker on the
radiator of power module.
Poor radiation, heat exchanger
is dirty
Remove obstructions
and clean
Outdoor fan runs Confirm if there is voltage output and balance of
voltage between any two phases of U, V and W.
Yes
No
Whether module type
Replace the power module
is correct
Normal
Abnormal
Normal
Abnormal
Measure the three-phase
Replace the module
with correct type
resistance of compressor
Replace the
Whether cylinder of
compressor is stuck
compressor
If the unit runs normally after connected
with the new compressor for trial run, the
cylinder of original compressor is stuck
3
2
