Ancient Vaillant Geyser help please

[Sid Viscous]

Hi Guys, I've come across a Vaillant MAG SINE 250/7 ATZFW:H. I've never come across one before & haven't worked on owt like it since college (then I managed to break theirs!!). Basically, when you open a hot tap, water flows but the unit doesn't light. I believe it operates via a diaphragm. Would it be easier to replace the whole water valve? Cuzzy won't want to fork out for a whole new unit, which would be my preferred option.............BIN IT!!!

 

[Reg Man]

Certainly is the diaphragm, think you can still get them as a spare part but most suppliers try to sell you the whole fitting (Valve body). Diaphragm washer about £10 whole thing £100.