Adding a 1 zone ufh manifold to a combi boiler with an integral 3 way valve Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[Ady25]

Hi. I'm looking at fitting a 1 zone ufh manifold in my extension with independent controls and want to know if it's possible to add this to an existing combi boiler with a integral 3 way valve for radiators and hot water. Any help would be greatly appreciated. TIA

[ericmark]

I am sure it is, but much depends on what you already have. EPH for example do zone thermostats which work as master/slave I think up to 10 zones using OpenTherm.

But all down to what you have, although called combi boilers some are really just a small water store inside the boiler so you can do away with the external tank, specially with oil.

And some combi boilers can modulate 6 kW to 32 kW and are designed to extract the latent heat from flue gases.

The combi boiler does not always gain the latent heat, but where it does the return water temperature is important. In the main under floor has a return water temperature of 30 degs C or less, and they work using a second pump circulating the water and add some extra hot as it cools down.

The aim is often to use analogue as much as possible, the boiler wants gradual change and you can't get that with on/off (digital) control.

But the guys fitting it are called engineers, which means University educated, and the systems get rather complex.