54
Installation and Maintenance
Service Manual
3. IPM protection , over-phase current of compressor
Main check points:
(1) compressor COMP terminal (2) power supply voltage (3) compressor
(4) charging amount of refrigerant (5) air inlet and air outlet of indoor/outdoor unit
NOTE:The control board as below means the control board of outdoor unit.
Y
Y
Y
Y
Y
Y
Y
N
N
N
N
N
N
N
Y
Put through the
power and turn
on the unit
IPM occurs when
the unit has operated for a
period of time.
Check the connection between
the control board and the
compressor according to the
electric wiring diagram.
Check whether the
compressor wire (UVW) is connected
and the connection sequence
is correct.
Measure the voltage of terminal
L and terminal N of wiring board
with AC voltmeter.
Connect the compressor wires
correctly according to the electric
wiring diagram, and then put
through the power and then turn
on the unit
Measure the resistance among
three terminals (UVW) with the
resistance measuring meter.
Check the power supply
voltage and make it resume
to the range of ±10% of
rated voltage.
Is the voltage between
terminal L and terminal N of XT in the
range of ±10% of rated
voltage?
1.Check whether the heat exchanger of indoor/outdoor unit is dirty and whether the
heat exchanger is covered by foreign object
2.Check whether the indoor fan and the outdoor fan operate normally;
3.Check whether the system pressure is too high;
4.Check whether the pressure is too high because there are too much refrigerant;
Is the resistance value
for the three terminals of compressor
are almost the same?
Is the resistance
more than 500M
Measure the resistance among
three terminals (UVW) and the
copper pipe with the resistance
measuring meter.
Are there abnormal
circumstances described
as above?
Correct them basing on
the Service Manual and
then put through the
power and then turn on
the unit.
Replace the compressor
Does the unit operate normally?
Replace the control
board
End
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