Carrier 619FB Service Manual page 25

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