Evohome - adding single zone wet UFH

[greenslime30]

Ladies and Gentlefolks,

Think this is my first post after a bit of lurking.

Anyway I come to seek knowledge and enlightenment.

Coming to the later stages of a kitchen diner extension, which as part of the spec has had a single zoned wet UFH system fitted. It has yet to be plumbed into my current heating system. I have evohome running the rest of the house, radiators and hot water (I have a hot water tank and cold in loft). Today the builder announces that the new UFH system won't work with evohome. It is my understanding that Honeywell do a UFH kit for evohome and after some research I think it could be run off a wireless thermostat and relay.

The new UFH is single zone and the plumber intends to tap into the current heating pipes to make it work.

Anyone got a clue about evohome or how it works? Or more specifically how to solve the above problem? Trying to go armed with all the ammo when I see the builder and plumber next.

Thanks muchly

[clockworks]

I have a simple Evohome setup, and have just fitted another for my mother. No experience of UFH though, so I've just had a read of the Honeywell UFH controller manual. It looks like it can be configured for just about any wet system.

Maybe the complexity is putting your builder off?

Try asking The Evohome Shop, via their forum

[greenslime30]

Thanks for the tip....I'll pop over and see what they have to say!

Cheers

[catfood12]

It will work as just an additional zone. You will have to change your existing diverter 3 port valve for two separate two port valves, and a third two port valve for the UFH manifold. If you don't do this, then when UFH is calling for heat, and DHW isn't, the DHW will still see flow, as the 3 port valve's default position is for DHW.

I can see a wiring and logic nightmare if you try and connect the UFH controls off the existing CH, and connect it's flow and return off the existing CH pipes. It should be connected to flow & return off the boiler, behind a two port valve. You'll find you want the UFH running for different hours (on and off earlier) than the CH.

[Andehh]

For Equipment wise, you will need the below I think. I have more or less exactly the setup you have (but I later added UFH loops to our bathrooms during their renovations)

https://theevohomeshop.co.uk/honeywell-evohome/22-...

https://theevohomeshop.co.uk/honeywell-evohome/78-...

https://theevohomeshop.co.uk/honeywell-evohome/43-...

For assistance explaining it, ring Richard @ The Evohome Shop on 0333 250 2543. It was a couple of years ago for me, and my electrician spoke to Richard and just sorted it all for me.

Make sure you have a Pen & paper to hand, as he will explain everything you need to do in one phone call. Very helpful chap!