Vaillant V 12-025 HWI Training Manual page 23

E7 outdoor feedback fault
E7 error diagnosis and solution:
Check whether the winding resistance and
operation current of the compressor are normal
Y
E
S
Check whether the high and low pressure
is normal when the unit is running.
Y
E
S
Check whether the indoor and outdoor wiring
is right connect them again
Y
E
S
Check whether the contact of the inserter
on the circuit board and the connection are well
Y
E
S
Check whether the signal feedback wire
is disconnected
N
O
Check whether the supply power
is phase-lacking or phase opposition
N
O
Check whether the AC electromagnetic
contactor is well according to the circuit diagram
Split Type Installation Manual
Replace the compressor
NO
Check unit if it is leakage
NO
and fill the refrigerant again.
Connect them again according
NO
to the circuit diagram
NO
and make sure it's well connected
Connect them again
YES
according to the circuit diagram
YES
and make sure it's well connected
Service Diagnosis 7
Re-connect it,
Re-connect it,
EN 23