Open therm and distinct zone valve wiring to the same heat link

[Kiougar]

Hello,

I have a combi boiler that supports open therm. I also have three distinct zone valves (one for each floor).

I understand that I can connect one nest learning thermostat to each zone valve but I'm guessing I will lose any open therm features (because OT connections won't be used). Is this assumption correct?

Can I still connect the OT to only one of the three heat links, while having the zone valve connected to the same heat link?

Can I connect all OT connections in parallel for all three heat links (it shouldn't be necessary, I'm just curious)?

Thanks in advance!

[AlexD]

Thanks for reaching out to us here @Kiougar . I would be happy to try and assist. 

Since you have a zoned system you'll need to connect 1 thermostat with their Heat Link to each zone valve. You are correct in your assumption as when you set up the thermostat type of boiler you can only use OpenTherm or the other control method.

I wouldn't recommend connecting the Heat Links OT connections in parallel. 

[Kiougar]

Thanks for the reply @AlexD !

Is it possible, for one Heat Link only, to have the OT connections connected with the boiler (so that at least it can manage the heating water temperature efficiently) while also controlling the zone valve with the 3-4 pins?

Basically, have both OT and 3-4 pins connected and when the thermostat says "heat", the 3-4 are "connected" (so the valve turns on) and the OT sends the necessary signals.

Is that possible?

[Vladut]

In this situation I would not recommend this kind of installation as the thermostat and the Heat Link may cause unexpected behavior and/or damage to your heating system.