Expansion Vessel - What Pressure?

[WannabeMKII]

Hi,

We've recently purchased a property and noticed it has an 8 litre BOSS Expansion Vessel. Unfortunately, we didn't receive any paperwork about it, so we know very little.

Therefore, I was hoping someone here would be able to advise what pressure the vessel should be set at, or any other general user comments?

Thanks.

 

[glasgowgas]

what is the expansion vessel used for

central heating or potable water

 

[WannabeMKII]

what is the expansion vessel used for

central heating or potable water

Apologies for the lack of info, I've only quickly looked to try and find out more info, as I've never seen one before.

I'll take a proper look next time to try and work out exactly what pipes it's connected to. However to be of best help, what specific things do I need to look? What pipes it's connected to etc?

What I can tell you is that it's in the airing cupboard just above the hot water tank, as it's not a combi boiler.

Thanks and apologies for a poor opening post.

 

[glasgowgas]

if it looks anything like this....



View media item 18779
your boiler has been converted to a sealed system, and exp vessel should be 0.8 to 1 bar

if you have an unvented hot water cylinder, refer to manufacturers instructions

 

[WannabeMKII]

if it looks anything like this....



View media item 18779
your boiler has been converted to a sealed system, and exp vessel should be 0.8 to 1 bar

if you have an unvented hot water cylinder, refer to manufacturers instructions

That looks like it, but I believe it's an 8 litre model.

How can I tell if it's an unvented hot water cylinder?

Thanks.

 

[WannabeMKII]

Hi all,

Well, I managed to take some photos last night with my phone;

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• WannabeMKII
• 22 Jan 2010
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• WannabeMKII
• 22 Jan 2010
• 1

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• WannabeMKII
• 22 Jan 2010
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Hopefully this'll help...

Thanks.

 

[glasgowgas]

the gauge underneath the exp vessel should read between 1 and 1.5 bar cold

to the right of the gauge is a silver braided hose. follow the hose and it comes to a 1/4 turn black handled valve. this is mains water. you would turn the valve slowly until gauge reads between 1 and 1.5 bar

this water is being added to your central heating system (rads and pipework and cylinder htg coil as it is now pressurised. whatever comes out (air from bleeding rads and any small leaks and weeps) must be topped back up

if when central htg is running and the gauge pressure rises above 3 bar
a safety valve will lift and dump excess water to outside. if it does this the expansion vessel may need recharged using a bicycle pump to 0.8 bar

check all the FAQS at the top of the page for a detailed run through of how to do this

 

[WannabeMKII]

Thanks glasgowgas.

Apologies for not getting back sooner, but I didn't get an email notification of an update to the topic and have only just got around to checking.

I think it's set to just below 1 bar now, so will increase it to about 1.25 bar and monitor it from there.

Thanks for everyones help, much appreciated!!!

 

[Nige F]

to the right of the gauge is a silver braided hose. follow the hose and it comes to a 1/4 turn black handled valve. this is mains water. you would turn the valve slowly until gauge reads between 1 and 1.5 bar




check all the FAQS at the top of the page for a detailed run through of how to do this

remove braide hose after