Carrier 42QFD048D8S Service Manual page 104

Is the power voltage normal?
Is the power voltage normal?
Yes
Is the outdoor terminal voltage
Is the outdoor terminal voltage
normal？
normal？
Yes
Is the voltage between L and N
Is the voltage between L and N
normal？
normal？
Yes
Is the input voltage of bridge
Is the input voltage of bridge
rectifier normal？
rectifier normal？
Yes
Is the voltage between P and N
Is the voltage between P and N
properly wired according to
properly wired according to
Index？
Index？
Yes
Is the connecting wire
Is the connecting wire
between the main board and
between the main board and
the IPM board connected
the IPM board connected
tightly?
tightly?
Yes
Is the connecting wire of the
Is the connecting wire of the
compressor is connected
compressor is connected
correctly or tightly
correctly or tightly
Yes
Is the outdoor unit
Is the outdoor unit
ventilation in working order?
ventilation in working order?
Yes
Is the outdoor fan running
Is the outdoor fan running
properly?
properly?
Yes
Replace IPM Board. Is the problem
Replace IPM Board. Is the problem
resolved?
resolved?
No
Replace the outdoor main PCB. Is
Replace the outdoor main PCB. Is
the problem resolved?
the problem resolved?
No
Is the compress is
Is the compress is
running normally?
running normally?
Yes
Check whether the refrigerant system is
Check whether the refrigerant system is
in working order
in working order
Note: For certain models, outdoor PCB could not be removed separately. In this case, the outdoor electric
control box should be replaced as a whole.
Index:
Restart the unit when the power supply
Restart the unit when the power supply
No
Are the power wires
Are the power wires
No
connected properly?
connected properly?
Are L and N wired
Are L and N wired
No
correctly?
correctly?
Is the bridge rectifier
Is the bridge rectifier
No
properly wired?
properly wired?
No
Reconnect the main board
Reconnect the main board
No
and IPM board
and IPM board
Reconnect he connecting
Reconnect he connecting
No
wire of the compressor
wire of the compressor
Make sure that the outdoor unit is
Make sure that the outdoor unit is
No
ventilating properly
ventilating properly
Please refer to the solution of the
Please refer to the solution of the
"fan speed is operating outside of
No
"fan speed is operating outside of
the normal range" malfunction.
the normal range" malfunction.
No Replace the compressor
Replace the compressor
 Troubleshooting
returns to normal
returns to normal
Reconnect the
Reconnect the
power wires
power wires
Reconnect L and N
Reconnect L and N
Reconnect the
Reconnect the
bridge rectifier
bridge rectifier
Is the bridge rectifier
Is the bridge rectifier
operating normally?
operating normally?
Yes
Replace the PFC module(If This has not
Replace the PFC module(If This has not
been done already)
been done already)
No
Are the reactor or
Are the reactor or
Inductance wired
Inductance wired
properly?
properly?
Yes
Are the reactor or
Are the reactor or
inductance normal?
inductance normal?
Yes

No Replace the bridge rectifier
Replace the bridge rectifier
No Reconnect the wiring
Reconnect the wiring
Replace reactor or
Replace reactor or
No
inductance
inductance