Valve between outflow and return pipes

Dave Cooper · 28 Sep 2019

There is a valve connected between the outflow and return pipes just under my combi boiler. What is this for and should it be open or closed?

CBW · 28 Sep 2019

Without seeing it (photo would help) sounds like a bypass valve.

Depending on which Combi you have it might be needed?

Hugh Jaleak · 28 Sep 2019

Possibly it's for filling and/or topping up the system. Should be closed unless system requires water. Could be a bypass. Need a pic please to say for certain.

Dave Cooper · 28 Sep 2019

Dave Cooper · 28 Sep 2019

Please let me know if you guys need more info

denso13 · 28 Sep 2019

It's a bypass, just open it a quarter turn (using the spindle) and all should be ok.

Dave Cooper · 28 Sep 2019

What would happen if it was fully open or closed?

denso13 · 28 Sep 2019

Dave Cooper said:
What would happen if it was fully open or closed?

There is no danger either way but it is a requirement for some boilers as mentioned above. If it is just slightly open you shouldn't have any issues.

Hugh Jaleak · 28 Sep 2019

A bypass is fitted to allow some circulation through the boiler if all the rad valves close down. Leaving it fully closed will prevent that happening, and could possibly cause system damage. Having it fully open will allow a direct path for the flow from the boiler to take the easy option, and may result in the system taking longer to heat up. Personally would leave it well alone, valve might start leaking from the gland if you tamper with it!

ianmcd · 29 Sep 2019

It is a by-pass as already said by others, it is set at install. if everything working as it should forget it is there and leave it alone

Dave Cooper · 29 Sep 2019

Thanks eveyone.

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Valve between outflow and return pipes

Similar threads