TRVs able to request heat from a zone controller in order that valves open

Marsh

In scenarios like mine where a house has separate zones with valves (i.e. upstairs and downstairs) currently TRVs are effectively slaves to the zone controller thermostat which opens the valves. This means that the zone controller thermostat has to be calling for heat in order for any TRVs to work.

The ideal would be that a TRV could request heat and open the zone valve itself. Alternatively, if this is not possible, then for the TRVs to be able to call the thermostat and increase the temperature of that so it turns on, requests heat and therefore opens the zone valve.

XKRMonkey

I was thinking about this myself in the context of summer and winter shutdown, but I think it's another "problem" that affects a limited market.

Your best bet may be to look at using other SMART technology to operate the zone valves, using tools like IFTTT to open and close the zone valves, based on the temperatures reported by the thermostats or SRVs in that zone. This is a lot of effort (even if not a massive cost) and could become more complex than it needs to be.

The reality is that the need for grouped zoning using traditional zone valves really disappears when you can zone at a radiator or room level using SRVs. Your best bet may simply be to get your plumber to come and remove the zone valves completely - this is what I did, because it's a layer of complexity that simply adds to the effort without really bringing any value in return. It's an easy task to remove the zone valve and insert a short length of copper pipe using a couple of 22mm connectors. That way, you could very easily reinstall a zone valve later if you found a need for it again.

cbd20

@Marsh I'm slightly confused by this request. Admittedly I've only got one zone in my house rather than two, but can't Tado do exactly what you want already?

If each TRV is assigned to the correct zone controller then they can ask that zone controller to open the valve, even if that Zone controller itself is not actively calling for heat.

You can assign a zone controller to a TRV, by going to "Rooms and devices" in the app and clicking the Room name. At the bottom, assign a zone controller according to which one you need. Surely this works for a two zone system?

samd

@Marsh Does this not cover your issue

2. Wired Smart Thermostats control zone valves and Smart Radiator Thermostats are installed in the rooms (recommended)

The Wired Smart Thermostats control the zone valves based on the heat demand of any room in that zone.

The tado° devices in each zone communicate with each other. The Smart Thermostat opens the zone valve when any room with a Smart Radiator Thermostat in that same zone needs heating. Even if the temperature in the room with the Smart Thermostat is already reached. For this setup, it is important to ensure that the correct zone controller is selected for the rooms with Smart Radiator Thermostats.

P33dubs

As @cbd20 suggested it can do what you want. If you already have two physical zones on your boiler system, then you will need match boiler controls so you can itemise which trv’s call which heating zone; if you just remove the second system zone from your boiler, TADO can do what you are after by selecting only the coldest rooms on each floor to actually fire the boiler, all other TRVs just have a temperature schedule and open close to the temperature without call the boiler.