Bypass Valve Setting

[diyscotland]

I have a Vokera Linea 28 Combi boiler. It has been loosing pressure on the heating system for a while, and I think I have isolated it to the bypass valve located between the flow and return pipework. This is an external valve located below the floor. I am looking to replace it, but I have noticed that it is currently set partly open. How do I know how to set the new valve position?....or should it be closed?
Also, what is its purpose, as if even partially open it must allow flows to re-circulate directly back into the boiler?

Thanks in advace.

 

[Al-Glasgow]

If it is a gate valve, then when you remove it you will be able to look thru it and see how restricted it is.

Al

 

[jobloggs]

Are you losing pressure due to a leak in the gland of the valve around the spindle where it comes out of the valve. If so you could repack the gland and tighten the gland nut without removing the valve.

You could think of replacing it (if it is a gate valve) with an automatic bypass valve which only opens when pressure builds up when both CH & HW stats are satisfied. (search google for details)

 

[diyscotland]

Are you losing pressure due to a leak in the gland of the valve around the spindle where it comes out of the valve. If so you could repack the gland and tighten the gland nut without removing the valve.

You could think of replacing it (if it is a gate valve) with an automatic bypass valve which only opens when pressure builds up when both CH & HW stats are satisfied. (search google for details)

Thank you...it is a manual gate valve. Hard to tell where it is leeking as it is a tight spot to access!! But it does only seem to leek when system is cold.

 

[ChrisR]

Well it'll bethe compression fittings onm the pipe, the join in its middle or the seal round the spindle. Coloured tissue paper is very handy for finding moisture - 70's purple loo paper was best!

It's probably the gland/spindle seal - do it up anyway!