Vaillant V 12-025 HWI Training Manual page 26

7 Service Diagnosis
E5
E3 error diagnosis and solution:
Check if the power supply of fan motor is well
connected
Check if the fan motor is broken
Check if the controlled silicon or any electric
components are broken
Check if the cross flow fan runs smoothly
E8
E8 error diagnosis and solution:
Check if the resistance value
of indoor coil sensor is normally.
Check if the indoor fan motor runs normally.
26
PG fan motor failure
Y
E
S
N
O
N
O
Y
E
S
Re-connect it, and make sure it's well connected
NO
YES
Replace the controlled silicon or indoor PCB
YES
NO
NO
NO
Replace the fan motor
Re-fix the cross flow fan
Replace the sensor
Replace the fan motor
Split Type Installation Manual