Blanking off a tap connector

[bblaukopf]

The expansion vessel on my boiler is leaking. Replacing it is impossible, s o I intend to fit another nearby, on the return. Obviously I'll need to dis connect the old one - given it leaks, and the only place I can sensibly do this is at the expansion vessel end of the flexible hose running to it. I a ssume this will be a 3/4" BSP tapered, and therefore I want this part.

Does that sound sensible? I intend to tee into the return just underneath t he boiler (though it would be easier to do it in the airing cupboard, the m anual says as close as poss...). Is there any requirement to have a dedicat ed PRV on the expansion vessel?

[Andrew Gabriel]

Tap connectors are normally parallel threads and seal on a washer, but I don't know what your expansion vessel connector is.

Ideally, you want the expansion vessel connected as near as possible to the pump inlet. Constant pressure at this position reduces cavitation on the pump impeller, which should give longer pump life and reduce noise.

You have to have a pressure relief valve in the circuit, as near as possible to the boiler. There isn't normally a PRV on the pressure vessel, just a tyre valve so you can pump up the dry side with a bicycle pump if necessary.

[newshound]

While you are doing this, you might want to think about including a valve to isolate it, and a drain c*ck, to make it easier to check and repressurise the vessel if necessary in the future.

No need for a separate pressure relief valve that I can see.

[bblaukopf]

e, so I intend to fit another nearby, on the return. Obviously I'll need to disconnect the old one - given it leaks, and the only place I can sensibly do this is at the expansion vessel end of the flexible hose running to it. I assume this will be a 3/4" BSP tapered, and therefore I want this part.

Ah, it looks like the expansion vessel is BSPP too. My mistake. Thanks.

ould be easier to do it in the airing cupboard, the manual says as close as poss...). Is there any requirement to have a dedicated PRV on the expansio n vessel?

Ta.

Presumably the PRV inside the boiler counts?

I'll add an isolating valve, disinclined to bother with a draincock given a ) they're my soldering nemesis, and b) it would be simple enough just to re lease the compression joint if needed - there won't be anything underneath that minds getting wet, and a towel will cope with the spray once the thing is isolated.

Fitting prices seem to have gone through the roof since the last time I did any plumbing... at least I've still got a length of copper hanging around!

Thanks,

Ben

[bblaukopf]

so I intend to fit another nearby, on the return. Obviously I'll need to d isconnect the old one - given it leaks, and the only place I can sensibly d o this is at the expansion vessel end of the flexible hose running to it. I assume this will be a 3/4" BSP tapered, and therefore I want this part.

the boiler (though it would be easier to do it in the airing cupboard, the manual says as close as poss...). Is there any requirement to have a dedic ated PRV on the expansion vessel?

Subsequently realised that instead of tee-ing in, I could just connect the old flexi (which was actually 1/2" bspp) to the new expansion vessel via little bit of a pipe for a lot less effort than draining down the system an d putting a tee in. So I did, and I'm enjoying watching the system pressure gauge do - well nothing really, for the first time in a while :)