UFH + rads + Nest + OpenTherm

[EvilDonut]

so I want to add UFH to my existing single-zone single-nest heating system, the nest is wired to my Combi via OpenTherm.

I want to keep the OpenTherm if possible as it helps the boiler modulate for peak efficiency.

It is not possible to chain nests together unless you use the dumb On/Off control method, so I’d have to sacrifice OpenTherm.

Can anyone think of any nice innovative solutions that will get me what I want?

I was thinking dual-zone with one zone controlling a zone valve and one wired direct to boiler, but that would only allow On/Off for the zone, and would only work when the master Nest was on.

I also thought about having smart TRVs on all my rads, and making some kind of software-based controller (on my raspberry pi) to control them based on either a schedule or another nest. The nest would then mostly just control my UFH

 

[muggles]

The Honeywell T6 Lyric is capable of two-zone OpenTherm, and provides the same functionality as Nest with an upgraded version of the OpenTherm protocol

 

[EvilDonut]

If only I’d asked this question before buying the nest...

I’d then have found the evohome too which also does something like that and gives me indepentent control of each room.

 

[picasso]

What boiler do you have ?

 

[EvilDonut]

Ideal vogue c32, 3rd gen nest

 

[muggles]

Sell the Nest on eBay