Expansion vessel replacement in a Vaillant Turbomax 828/2E

[Milsec]

The expansion vessel has gone the boiler unfortunately. I say this because water as well as air came out when I pressed on the valve. I had hoped that the loss of circuit pressure was just due to a faulty PRV (which also needs to be replaced).

It doesn't look feasible ( for me anyway) to remove the faulty unit due to inaccessibility of the union nut and the inadequate clearance at the top of the boiler prohibiting the removal and refitting of the vessel.

So I was wondering what size of external vessel I would need (the same as the original?) and the best place to 'T' it in . I've read it goes in the CH return leg of the pipework but are there any other factors to bear in mind when fitting it? Do I have to stick with a Vaillant part if there are cheaper alternatives?

As a matter of interest how does the pipe connecting the (original) vessel fit into the rest of the boiler tubing, it looks like a push in connector held with a clip? If this is all it is could I attempt to remove it and connect the new vessel to this point?

Thanks all,

[Andrew Gabriel]

I don't think it's a major issue, but some boiler instructions (in cases where it's not integral) say it should be near the pump inlet in the pipework. My guess is this helps ensure the pump sees a steady pressure as valves open/close and the pump starts up, and this may reduce cavitation inside the pump.

Certainly not if you're fitting it outside the boiler.

[Ed Sirett]

I presume you've read the FAQ on account of the questions you are now asking.

You should be looking at about the same volume vessel as before (assuming it was adequate); 12 litres should do it.

You need to find a suitable place somewhere on the return pipework. Leave the failed vessel in the boiler. The official maintenance action involves removing the boiler from the wall! Set the new vessel to 0.8 bar on the dry side less/plus 0.1 bar for every meter of altitude above/below the boiler.

HTH

[geoff]

It's a diybanter - prolly doesn't have the first idea where to look

[Milsec]

Ed, yes I did read your FAQ which did point me in the direction of th PRV and then to the expansion vessel. Many thanks for that and your advice (and your previous help with th divertor valve)

-- Milsec