Carrier 619FB Service Manual page 36

3. IPM protection, de- -synchronizing malfunction, phase current of compressor is over current (AP1 below is control board of outdoor unit)
Main detection points:
S Is the control board AP1 and compressor COMP well
connected or are they loose? Is the connection sequence
correct?
S Is the voltage input in the normal range (test the voltage
between L1, L2 of the wiring board XT with a DC voltage
meter)?
Malfunction diagnosis process:
Energize and
switch on
IPM protection
occurs after the
machine has run for
a period of time?
Please confirm:
1. If the indoor and
outdoor heat
exchangers are
dirty?
2. Are the indoor
and outdoor fans
working normally?
3. If the environment
temperature is too
high, resulting in
the system
pressure exceeding
the high pressure
threshold.
4. Is the unit
overcharged?
5. Other conditions
resulting in the
system pressure
being 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 connection
order 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
Yes
terminal L and N
on the wiring
board XT)
Voltage between
the two ends of celectrolytic
Yes
Y
capacitor (test3) is
higher than
250V
No 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?
No N
If there is any
abnormality
described above?
No
N
Connect the control panel
AP1 and compressor
COMP correctly according
Yes
Y
to the Electrical Wiring
Diagram. Then, energize
and start the unit.
If the
resistance is
normal?
Resistance higher
than 500MΩ?
Replace the
control panel
Fig. 39 – Troubleshooting
S Is the compressor coil resistance normal? Is the
compressor coil insulated to the copper pipe well?
S Is the coil blocked with dirt and debris?
S Is the charge correct?
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.
No
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
Yes Y C2. Then, energize
and start the unit.
Replace the
control panel AP1
Take corrective actions
according to Technical
Yes
Y
Service Manual, and
then energize and start
the unit.
Replace the
control panel AP1
Does the unit
operate
normally?
Replace the
compressor
No N
COMP
N
No
Yes
Y
AP1
END
36
Check the supply
voltage and
N
No
restore it to
210VAC~250VAC
Does the unit
No Y
N Yes
operate
normally?
Reconnect the
capacitor C2 according
to Electrical Wiring
Yes Y
Diagram. Then,
Restart the
unit.
Does the unit
Yes
No
N Y
operate
normally?
Does the unit
Yes Y
operate
normally?
N
No
If the unit can
Yes
Y
work normally?
N
No
Yes Y