Vaillant Ecotec plus F54 F29 F28 part two for the eyes of gas engineer only.

10 Faults stored in the circuit board can be retrieved and in this case F54 F29 and F28 indicating unable to Standish ignition due to mainly gas or gas valve issue or the printed circuit board issue . It is important to carry out further tests as in video 2 to isolate if it is faulty gas valve or PCB
Select The power supply cables to the gas valve .
Select the two cables , each having two cables coloured blue and red.
The top one should get 22v dc at ignition when the gas valve is powered by the pcb while sparking.
The bottom one should change the dc voltage from 22 volts to between 12 to 16 vdc ( 12, 13 , 14, 15 or 16 )
If these tests are satisfactory then the PCB can be excluded from causing the fault.
Concentrate on the gas valve inlet side and notice the standing - static gas pressure and then check with manometer if the pressure drop is 4 Mbar at the ignition? If no drop , indicating gas valve is not opening and is at fault.

[@yensabi]

All the years I’ve been watching your videos this is the first time I’ve heard you speak on one of them....😃
On vaillants usually 8/10 times it’s dodgy solenoid...👍

[@deano-qj9tj]

Any tips on getting the little electrical connectors out? Sometimes they seem to get stuck

[@johnackers6311]

The speech is too quiet for most of the video.