Carrier 538FEQ009RBGA, Service Manual

Page: 25 / 94

25
4. Malfunction of Over current Protection E5
No
No
No
No
Yes
No
No
End
Yes
Malfunction is
eliminated
Is the supply voltage unstable
with big fluctuation?
Is the supply voltage too low
with overload?
The fan is abnormal? Fan
speed is too low or fan doesn’t rotate
Measure the
current of the main board
with a clamp ampere meter. Is the
current higher than the value of the
overcurrent protection?
Is there blockage inside
the system? (Filth blockage, ice plug,
greasy blockage
Is the compressor running
abnormally? Is there abnormal sound or oil
leakage; is the temperature of the shell
too high, etc.?
Is the indoor / outdoor
heat exchanger too dirty,or are the air inlet
and outlet blocked?
Normal fluctuation is within 10 % of the rated
voltage on the nameplate
Malfunction is
eliminated
No
No
No
No
No
No
No
No
Malfunction is
eliminated
Malfunction is
eliminated
Malfunction is
eliminated
Malfunction is
eliminated
Malfunction is
eliminated
Malfunction is
eliminated
Troubleshooting
for E5 malfunction
Adjust the supply voltage to maintain it within
normal range
Clean the indoor and outdoor heat exchangers
and remove the blockage of air inlet and outlet
Check the motor and reinstall the motor to have
the fan run normally
Replace the mainboard
Replace the mainboard with the same model
Flush the heat exchangers with high pressure
nitrogen
Replace the mainboard with
the same model
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Fig. 28 – Troubleshooting