Red wheelie valve in airing cupboard

[bob the bridge]

Could you please tell me what the function of the red "Wheelie" valve, (picture attached) situated in my airing cupboard and whether it should be open or closed. Thanks

 

[oz-plumber]

It's called a gate valve.

The function might be as a by-pass valve.

Count the turns from fully open to fully closed and go somewhere in the middle.

What's the problem with the system?

 

[Riley]

I'd say defos bypass

 

[bob the bridge]

Many thanks for the reply, no real problem. I did not know what this valve was for. Nobody seemed to know. One guy told me it was there to assist in draining down the system but that did not make sense to me. The only thing I noticed is that when the valve is fully closed with the CH off, the pipework makes a rushing noise. I have only just had the system refurbed and did not want to mess things up. thanks again.

 

[Riley]

As Oz says it needs to be open

 

[kozak1968]

It looks like a basic bypass which will let water flow when both two port valves are shut and the pump over run is active. The valve should be opened enough to let a flow through. Sometimes it is connected to the towel rail circuit.

 

[Best]

Might be better having a proper automatic bypass valve fitted, rather than an always slightly open gatevalve, in my opinion. Needs a heating engineer to do it and set it though.
My thinking is an auto bypass valve will remain fully closed unless the system needs it to open, when little or no flow is happening. But a gatevalve always open just derates the circulating pumps ability to pump around rads. Really just short circuiting a pump