Willis WMI12MH16S Service Manual page 87

Energize and
switch on
IPM protection
occurs after the machine has run for
a period of time?
Y
Please confirm:
1. If the indoor and
outdoor heat exchangers
are dirty? If they are
obstructed by other
objects which affect the
heat exchange of indoor
and outdoor unit.
2. If the indoor and
outdoor fans are
working normally?
3. If the environment
temperature is too
high, resulting in
that the system
pressure is too high
and exceeds the
permissible range?
4. If the charge
volume of refrigerant is
too much, resulting in
that the system
pressure is too high?
5. Other conditions
resulting in that the
system pressure
becomes too high.
Refer to the Electrical Wiring
Diagram and check if the
connection between AP1 and
COMP is loose and if the
connection order is correct.
If the connection
between AP1 and COMP is unsecure
or the connectionorder is wrong?
Use ohmmeter to measure the
resistance between the three
terminals on compressor COMP,
and compare the measurements
with the compressor resistance on
Service Manual.
Use ohmmeter to measure the
resistance between the two
terminals of compressor
COMP and copper tube.
Use AC voltmeter
to measure the
voltage between
Y
terminal L and N
on the wiring
board XT)
Voltage between
the two ends of celectrolytic
capacitor (test3) is higher than
250V
N
Stop the unit and disconnect
the power supply. Then, check
the connection of capacitor
C2 according to Electrical
Wiring Diagram.
Remove the wires on the two
ends of capacitor C2. Then,
use capacitance meter to
measure the capacitor C2.
Verify as per the
Parameters Sheet.
If capacitor
C2 is failed?
N
If there is any
abnormality
described above?
N
Connect the control panel AP1 and
compressor COMP correctly according
Y
to the Electrical Wiring Diagram.
Then, energize and start the unit.
If the
resistance is N
normal?
Resistance higher
than 500MΩ?
N
Replace the
control panel AP1
END
If the voltage
between terminal L and N on wiring
board XT is within
210VAC~250VAC?
Y
Restart the unit. Before
protection occurs,use DC
voltmeter to measure the
voltage between the two
ends of electrolytic
capacitor on control
panel AP1 (test3)
The connection
of capacitor C2 is loose.
N
Stop the unit and disconnect the
power supply. Wait 20 minutes,
or use DC voltmeter to measure
the voltage between the two
ends of capacitor C2, until the
voltage is lower than 20V
Replace the capacitor
Y
C2. Then, energize
and start the unit.
Replace the
control panel AP1
Take corrective actions
according to Technical
Service Manual, and
Y
then energize and start
the unit.
Replace the
control panel AP1
If the unit can
work normally?
Replace the
compressor COMP
N
Check the supply
voltage and
N
restore it to
210VAC~250VAC
If the unit can
N
work normally?
Reconnect the capacitor C2
according to Electrical
Y
Wiring Diagram. Then,
Restart the unit.
If the unit can
N
work normallv?
N
If the unit can
work normally?
N
Y
Y
Y
Y
Y