Carrier 38QUS012D8S Service Manual page 136

2.4.4.15. J3 Malfunction
Malfunction
conditions
Supposed causes
At first test the resistance between every two ports of U, V, W of IPM and P, N. If any result of them is 0 or
close to 0, the IPM is defective. Otherwise, please follow the procedure below:
J3 display
J3 display
PFC module protection
PFC module protection
Check whether the
Check whether the
connecting line between
connecting line between
main board and the PFC
main board and the PFC
module is connected tightly
module is connected tightly
Yes
Measure whether the voltage
Measure whether the voltage
between P and N is normal
between P and N is normal
refer to the Appendix 3？
refer to the Appendix 3？
No
Check whether
Check whether
inductance of PFC module
inductance of PFC module
is good? If the inductance is
is good? If the inductance is
good, the resistance of the
good, the resistance of the
two ports is 0
two ports is 0
Yes
Replace the PFC module
Replace the PFC module
Electrical Control System
decision When the voltage signal that IPM send to compressor drive
chip is abnormal, the display LED will show "P6" and AC will
turn off.
Wiring mistake
●
Faulty IPM board
●
Faulty outdoor fan ass'y
●
Compressor malfunction
●
Faulty outdoor PCB
●
Connect it tightly, check
Connect it tightly, check
No
No
Yes Replace the outdoor main board
Replace the outdoor main board
the
the
No Replace the inductance
Replace the inductance
normal or not
normal or not
Yes
Trouble is solved
Trouble is solved
Troubleshooting
134