Expansion Vessel

[shieldssecurity]

Hi,

I've just got an electric combination boiler and am a bit confused about a couple of things.

Firstly, in the instructions it says that the primary expansion vessel should be connected into the CH return at the boiler. Does this mean I just T off and install the vessel just before the 22mm enters the boiler.

Secondly, it says in the instructions that an automatic by-pass valve should be fitted on all models. I aint got a clue what this one is.

Any help will be greatly received.

Thanks

 

[Andy™]

not an expert on heating, but i think this is right

the bypass valve fits between flow & return. its there so the boiler doesnt self destruct if the flow is blocked. i.e all rads have thermostatic valves or some other problem

for expansion tank, yes, you could just tee form the return pipe at boiler

 

[kme]

With Andy here - on both points.

The auto bypass is a doofus which sits between flow & return, and, when it senses a pressure differential (such as pump pushing water at closed TRVs), opens to allow water to flow between flow & return.

Can be avoided if you have, for instance, a towel rail in the bathroom, with 2 lockshield valves instead of a TRV, which is always "on"; then the auto bypass isn`t necessary.



KME

 

[shieldssecurity]

With Andy here - on both points.The auto bypass is a doofus which sits between flow & return, and, when it senses a pressure differential (such as pump pushing water at closed TRVs), opens to allow water to flow between flow & return.

Can be avoided if you have, for instance, a towel rail in the bathroom, with 2 lockshield valves instead of a TRV, which is always "on"; then the auto bypass isn`t necessary.



KME

Actually thats a bit of good advice as there will be 2 towel rails with normal valves.

thanks

 

[kme]

Like your tagline, mate. Well said.

 

[stani]

manufacturers instructions say you should fit an ABV then you have to fit or the manufacturers will simply say its not fitted as per their instructions and the guarrantee is void,

 

[Andy™]

manufacturers instructions say you should fit an ABV then you have to fit or the manufacturers will simply say its not fitted as per their instructions and the guarrantee is void,

should, not must.

but still could cause problems incase of failure

 

[stani]

ABV's are easy to fit and usually come with concise instructions on how to set up

 

[ianmacd]

Actually thats a bit of good advice as there will be 2 towel rails with normal valves. thanks

They would need to be the boiler side of any motorised valves too.