Anyone got a part number for a Vaillant PRV

What's the system pressure, and are you having to top it up regularly? Does it leak continuously or only when hot? (Just wondering if the expansion vessel might be the problem, so it's going over pressure when hot, and then dropping under pressure when cold to due PRV releasing the excess.)

If it leaks when cold, it may have got some debris trapped in it. You might be able to release that by deliberately discharging a few short bursts through it using the knob.

Does it need something special, rather than a bog-standard one?

your supposed to turn the red knob every so often anyway, but i bet most people dont.

turning the knob clears out limescale and other crap that forms on the seal, as well as turning the seal around a bit to a new seating position, do it often enough and you hardly ever have to replace them, that's what i found out with boats and motorhomes with calorifiers which use a 3 bar prv anyway, the ones that need changing due to leaking the owners didnt even know it was there half the time, and the others thought turning it adjusted the pressure setting.

The pressure is dropping to the bottom stop daily. It seems to leak when cold but not as fast when hot.

I've done that already but I can try again.

No idea - all the ones that I've seen online list Vaillant numbers but just not mine. Are all 3Bar PRVs equal?

Mark

That's interesting - I've never heard that before but it makes some sense.

Mark

There are differences in fittings, compression verses combinations of BSP male/female, and also types with integral pressure guage, or not.

Vaillant could have had something special made for them though.

I think the Vaillant ones use a clip+O-ring type seal, as do many of the water components in the boiler.