What's this?

[WJAM29]

Hi,

I have this installed in my airing cupboard and it's making a rattling noise. Any ideas what it is? Is it some kind of pressure release valve? And I take it shouldn't rattle?

Many Thanks

Will

 

[TCCHeating]

Its an automatic bypass valve. And no, it shouldn't rattle

It opens up when the motorised valves close and creates a flow path for the pump overrun

 

[WJAM29]

Hi,

Thanks for the reply. Are they easy enough to change? The airing cupboard is in a bedroom so would like to stop the noise.

Many Thanks

Will.

 

[TCCHeating]

Yes easy enough to replace. Just order a replacement (90 degree 22mm auto bypass valve). You will have to drain the system, undo the two nuts, remove and replace with new bypass and refill. Make sure you set the new one so that it is closed when the heating/hot water is on, and opens when you turn the the heating/hot water off.

 

[WJAM29]

How do you set it? It almost sounds like it should be connected to the electrics? Is it not the case that when the hot water and heating turn off the pump overrun will increase the pressure in the system causing the valve to open? The more you wind the valve in the higher the pressure will build before it releases and vice versa?

Regards

Will

 

[TCCHeating]

Is it not the case that when the hot water and heating turn off the pump overrun will increase the pressure in the system causing the valve to open? The more you wind the valve in the higher the pressure will build before it releases and vice versa?

Regards

Will

Yes thats pretty much it. The trick is finding the sweet spot where it only opens on pump overrun. New valve will come with instructions on how to set it. They often come pre set to a default which is normally fine, but sometimes they need tweaking.

 

[WJAM29]

Thanks very much for the advice.

I wonder what I'll be doing this weekend?

Regards

Will.

 

[Agile]

I would say that its probably about the right setting of 3.5 m

Tony

 

[PullerGas]

Average system it's set at around .2 - .3 bar. But check your pump curve & system head.