I stumbled on the Opentherm Gateway in a search to make a zone controller for my house and I was wondering if and how it would work to enable zone control in my situation.
My situation is as follows:
- Nest thermostat V3 on ground floor controlling the boiler through opentherm.
- Ground floor where the Nest is located has underfloor heating
- Upstairs have multiple rooms with radiators and TRVs (controlled via Z-wave)
- Home assistant
What I'd like to do is independently control the underfloor heating and radiators. Currently the problem is that if I'd like to control the TRVs upstairs when the ground floor has already reached its desired setpoint, there is no hot water supply. What I now have to do is to raise the setpoint of the Nest to a degree or so higher, such that the boiler turns on, and heats the upstairs radiators. Now the ground floor is heated to a higher setpoint than desired.
How I'm planning to achieve this:
I am planning to install some servos on the heating system such that I can decouple it from the heating system (i.e. can turn the hot water supply off). My thinking to have the desired situation of independent zone control, is to have the Nest still control the boiler. If the setpoint is reached, and I want to heat upstairs, I would like to overrule the setpoint of the boiler, and at the same time close the servos to the underfloor heating. In this way, the ground floor is not heated unnecessarily.
My main questions are:
- Does above make sense or do you have a different suggestion?
- Does the OpenTherm Gateway allow me to overrule the Nest by having by setting the boiler to heat temporarily until the upstairs radiators have achieved their setpoint, without having this reported on the Nest as a raised setpoint?
- Any examples of the logic of such a system in Home Assistant? (otherwise I would be comfortable enough to make this from scratch, but maybe I can save some time