Carrier 38QUS014D8S2-1 - Page 91

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18.3.3 For the outdoor unit
18.3.3.1 Outdoor EEPROM malfunction(ODU E0/EC 51)
Yes
Replace the outdoor main PCB
Replace the outdoor main PCB
Power off, then restart the
unit 2 minutes later
Power off, then restart the
unit 2 minutes later
EEPROM: An electrically erasable programmable read-only memory whose contents can be erased and
reprogrammed using a pulsed voltage.
10.3.3.2 Condenser coil temperature sensor T3 is in open circuit or has short circuited(EC 52)
Outdoor room temperature sensor T4 is in open circuit or has short circuited(EC 53)
Compressor discharge temperature sensor T5 is in open circuit or has short circuited(EC 54)
Evaporator coil outlet temperature sensor T2B is in open circuit or has short circuited(EC 56)
Open or short circuit of outdoor unit temperature sensor(T3,T4.T5)(E4/ EC 50)
Check the connection
between temperature
sensor and PCB. Is it
properly wired?
Ensure proper connectionNo
Yes
Replace outdoor main PCB
Measure the resistance
value of the sensor. Is it
within acceptable
parameters?
Replace the sensorNo
Yes