EU tado with s plan ch +ufh

marcgjones

Hi all,

1st post here and trying to figure out..

I have not long done a renovation and installed a main eco30 combi, I also have a ufh wet system in my extension which hasn't been wired in, I have just installed 2 zone valves. I'm now at the point where I need to wire them up.

Ch is one system through the house with tado trvs in all bedrooms, boiler is connected via open therm.

I have bought a tado add on wired thermostat for the extension, boiler and receiver are in the extension.

I've tried reading so many things but none related exactly to my situation.

How the hell do I wire these two zone valves in, and going by what I've read I won't be able to use the open therm.

policywonk

This link give you your boilers installation guide:
https://ams3.digitaloceanspaces.com/boiler-manuals/main/Main-eco-compact-combi-25-30-ISIM.pdf
Look at page 42. The H block has two pairs of terminator which allow the digital control, ie Opentherm, to control the boiler in a more efficient mode than the usual dumb on off switching system.
As you've chosen to install two zones, each with their own motorised two port valves, this is my suggested framework:
1.. install hard wired smart thermostats to control each zone. These will drive the valves open and shut.
2. Install the EU wireless controller to act as the interface to the boiler asking for heat only when either or both thermostats demands heat.
3. Make sure your ufh manifold has a blending valve and dedicated pump set to deliver differential pressure. The wiring centre for the UFH should be triggered by the tado stat or stats assigned to it.
4. Make sure your radiator pump is set for differential pressure.
5. Note that digital controlled boilers study the change in outgoing to incoming pipe temperatures. This enables them to throttle up and down when the demand for heat is significantly different to other times. However if your default pump comes with the boiler it is important to ensure it is set before those two valves.
6.Write to Tado asking for a clear plan given your boiler, zones, etc. They will respond.

marcgjones

Policywonk...thanks for your reply.

System is currently up and running in open therm with a wireless room stat... (It'll be close to impossible to change to a wired stat)

Been unable to use ufh due to no zone valves.

Ufh does have a pump/blending valve etc.

I have bought a add on wired stat for this zone.

Is there any way that the wireless stat can control the zone valve? Or....as it'll be always on if I need to use the ufh...do I just wire up the ufh wired thermostat just to control the ufh.....I'll leave the ch zone valve manually open?

policywonk

Yes.

• Fit a wired stat to the zone valve
• Include that in the same room as the one with the wireless stat in the app
• In the app, goes to the room with both stats and set the wired stat as the zone controller.

marcgjones

Right....

This is what I did...the single zone ufh system is run of it's own fcu... Wired my wired thermostat into this...and connected it to the wireless receiver, I haven't bothered connecting up any of the zone valves..... upstairs is controlled by tado trvs so it's 3 rads downstairs and ufh.... blending valve controls the temp of the water to the ufh set to 40 degrees, so if and when the kitchen ufh calls for heat it fires the boiler. I could just remove the wireless stat in the living room now and run the downstairs rads and ufh off the kitchen thermostat.

Seems to be ok so far.

policywonk

Am genuinely not clear.

• What do you mean by the term FCU?
• You state - 'havent bothered connecting up any of the zone valves'. Do you mean youve forced all the zone valves to remain open, thus ensuring that the boiler's sensors determine the heat curve? That should work.