Question re hot water system...

[Glenisla]

I have a dual coil indirect cylinder system with inputs from a central heating boiler and aga.

Recently the AGA has not been providing enough hot water with no other apparent changes in the system.

I was investigating all the valves and controls to ensure they functioned properly - it appears they do.

I have a question about the photo below.

It shows the tank input from the boiler, top pipe hot in with a motorised valve controlled by the tank stat and heating controller and bottom pipe cold return.

Does anyone know why there is a bypass pipe fitted between the input and output pipes with the red manual valve fitted. And if you do know, under normal operation should the tap be open or closed?

Thanks

David.

Untitled

• Glenisla
• 14 Mar 2013
• 1

 

[Dan Robinson]

Its a by-pass to maintain flow through the boiler.

It should be set to whatever is suitable for the system.

Ideally you should change it to a differential by-pass such as the Honeywell DU144.

 

[Glenisla]

Thanks Dan.

How do I judge what is an appropriate setting for the system and can you explain the advantage of the upgraded bypass?

Thanks

 

[xr4x4]

Does the boiler only heat the hot water?

Seems an unusual place to put a bypass.

 

[Glenisla]

The boiler does heating and hot water.

 

[dcawkwell]

The bypass valve should be there just opened a crack to allow circulation for when the zone valve shuts down to allow some circulation.