Sealed CH System - expansion vessel required?

ln1234 · 2 Oct 2006

Been doing some work on the central heating system (moving/adding radiators), and have noticed that the system does not have an expansion vessel attached. It's a sealed system boiler, with a gravity fed hot storage tank (vented). My question is whether an expansion vessel should be fitted to such a system, and if so, where abouts it should be located? I did a test on the system by pressurising to 1 bar at cold, and checking what pressure it went up to at hot temperature - pressure went to near 2 bar.

cheers

bster · 2 Oct 2006

there maybe an expansion vessel within the boiler casing, or have you already looked ?

what boiler is it?

Fluffster · 2 Oct 2006

What model is the boiler are you sure the expansion vessel is not built into the unit.
Is there a pressure display gauge?
Pete

corgiman · 2 Oct 2006

what boiler is it

most sealed system boiler have an inbuilt ex vess

ln1234 · 2 Oct 2006

it's an old glowworm hideway unit - balanced flue model I think. no expansion vessel in there that I can see - unless it's hidden inside the unit where the burner is. The casing easily clips off from the front, and has a space where you could put the pump if you so desired.

does that clarify things a bit? cheers

corgiman · 2 Oct 2006

I am not sure that the hideaway has an over heat stat!!!!!!!!!!

but it should have an external expansion vessel

bster · 2 Oct 2006

how do you refill the heating system?

ln1234 · 2 Oct 2006

In the loft, there is a filling loop connected, which has a guage on it. I think it was converted from an old system as I don't see why the pipes would come into the loft if there is no rad there. The tank is on the first floor (in the airing cupboard) as well as the pump, and mid position valve.

If I have to fit one, wheres the best place to 'cut in' ?

corgiman · 2 Oct 2006

there must be something or the pressure would be higher then 2 when hot

ln1234 · 2 Oct 2006

actually, now that you come to mention it - there is a pipe coming off the hot feed (to taps) that has something like an air vent or similar stuck on it. The 22mm pipe just has that on the end and nothing else - is that the failsafe? cheers

corgiman · 2 Oct 2006

can u post a picture

keego · 2 Oct 2006

Try looking on the outside of the building for a pipe from the PRV, if you trace it back to the PRV then you wont be far from the expansion vessel.

Birmingham_Spanner · 2 Oct 2006

Am I missing the point here. (probably) But if the DHW cylinder is vented to atmosphere then the system cant be sealed. Old fashioned maybe, but not sealed.

Probably a dumb comment and feel free to ridicule me if I have missed something totally obvious.

corgiman · 2 Oct 2006

Birmingham_Spanner said:
Am I missing the point here. (probably) But if the DHW cylinder is vented to atmosphere then the system cant be sealed. Old fashioned maybe, but not sealed.

Probably a dumb comment and feel free to ridicule me if I have missed something totally obvious.

I think he is talking about the boiler etc brumm?

kevplumb · 3 Oct 2006

Probably a dumb comment and feel free to ridicule me if I have missed something totally obvious.

you have and they will

diynot

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Sealed CH System - expansion vessel required?

keego

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