Opentherm and multi-zone heating

[shaheerb]

Hi there,

I am installing a new system from scratch in my house. The current heating layout is all GF and 1F radiators are connected to a central manifold and my new extension will have water underfloor heating on a separate manifold. 

I have a nest learning thermostat and my intended boiler is compatible with opentherm (Main eco compact 30kW). I would like to have 2 zones, one for the original house (GF + 1F) and one for the extension underfloor heating with two nest thermostats. I have seen the nest multi-zone circuit recommendation on this page but I wanted to take advantage of the opentherm compatibility and true radiant feature - is this possible with a 2 zone system and what is the method to achieve this?

Thanks!

[ovidioj]

Hello  @shaheerb,

Thanks for posting in the community. 
You're right, the Nest Multi-Zone Circuit solution isn't ideal for taking advantage of both OpenTherm and True Radiant features. Here's how you can achieve your desired setup:

This setup is achievable using separate thermostats and OpenTherm communication. Here's how:

1. OpenTherm Connection: Connect the Nest Learning Thermostat directly to the boiler using the provided OpenTherm wires. This enables two-way communication for optimal heating control.
2. Separate Manifolds: Maintain separate manifolds for the radiator zone (GF + 1F) and the underfloor heating zone in the extension.
3. Nest Thermostat per Zone: Install a separate Nest Thermostat for each zone. One controls the radiators, and the other controls the underfloor heating.
4. True Radiant for Underfloor Heating: Enable the True Radiant feature on the Nest Thermostat controlling the underfloor heating zone. This optimizes comfort and potentially saves energy.
5. Zone Management: Use the Nest app to manage both zones, setting individual temperatures and schedules.

Please let me know if you have any other questions. Thank you.

All the best,
Jorge