Service Manual
(2) IPM Protection, Out-of-step Fault, Compressor Phase Overcurrent (AP1 below refers to the outdoor control
panel)
Main check points:
●Is the connection between control panel AP1 and compressor COMP secure? Loose? Is the connection in correct order?
●Is the voltage input of the machine within normal range? (Use AC voltmeter to measure the voltage between terminal L and N on the
wiring board XT)
●Is the compressor coil resistance normal? Is the insulation of compressor coil against the copper tube in good condition?
●Is the working load of the machine too high? Is the radiation good?
I●s the charge volume of refrigerant correct?
Fault diagnosis process:
Energize and
switch on
IPM protection
occurs after the
machine has run for
a
eriod of time?
Use AC voltmeter
to measure the
voltage between
terminal L and N
on the wiring
board XT)
If the voltage
between terminal L
and N on wiring
board XT is within
210VAC~250VAC?
Check the supply
voltage and
restore it to
210VAC~250VAC
Voltage between
the two ends of celectrolytic
capacitor is
Restart the unit. Before
protection occurs,
use DC voltmeter to
measure the voltage
between the two
ends of electrolytic
capacitor on control
panel AP1
If the unit can
work
normally?
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.
The connection
of capacitor C2
is loose.
Reconnect the
capacitor C2 according
to Electrical Wiring
Diagram. Then,
Restart the
unit.
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
C2. Then, energize
and start the unit.
Replace the
control panel AP1
Take corrective actions
according to Technical
Service Manual, and
then energize and start
the unit.
If there is any
abnormality
described above?
Replace the
control panel AP1
If the connection
between AP1 and
COMP is unsecure
or the connection
order is wrong?
Connect the control panel