whats this gate valve for?

[martin123]

Hi, Ive noticed on my central heating that I have a gate valve between my flow and return pipes that has always been open.

Whats the reason for having this valve and should it be closed?
My boiler is in the downstairs bathroom and also has a very small tank in the loft.
If my pic has worked it should be below.

Thanks

 

[Agile]

Its a gate valve used as a bypass. Its not the preferred method nowadays but it works.

It should be closed and with the system switched on from cold it should be slowly opened until the warm flow can just be detected warming the return side of the valve. This will indicate that there is just a little flow!

Ideally after it has been set the gland should be tightened and thr wheel heat taken off to prevent fiddling.

Tony

 

[martin123]

Cheers agile