Home heating automation

That'll work. The Drayton receiver will fit directly in place of the Climote. Wiring swap is straightforward, I'll post the the terminals numbers when I dig out the diagrams, though the electrician should be able to figure it.

Your Viesmann boiler pressure is critically low in that image. Should be at 1 Bar. It will cut out if it gets any lower.

TadoX, like its predecessors TadoV2 and V3, peculiarly don't allow more than one wireless thermostat to receiver in a configured 'home'. When replacing older thermostats wired to zone valves, just use Tado wired stats, but as your two thermostats are Salus RF, you need a two receiver solution.

The options are, use a TadoX wireless kit for the UFH zone valve, the receiver replacing the salus receiver. Then use a TadoX wired thermostat directly connected to the general radiators Zone valve. This will work well especially if it is possible to locate the wired stat in a general area, landing or living room or front hall. If however, it is difficult to wire it directly to the zone valve and run a wire pair to a location where the TadoX thermostat can measure a representative value of overall house temperature,( like the current Salus does, maybe it's located in the lounge, far from its RF receiver), there is still a solution.

As you are going to equip all radiators with TadoX TRVs, then each has it's own thermostat. To open the radiators Zone valve, you will need a receiver with a wired relay, and this is exactly what a TadoX wired stat can be configured to do. It will act as zone controller for all the TRVS, while it's own temperature measuring device is disabled for the 'room' it is in, which could be in a hot press next the the zone valve, wired in place of the radiators zone Salus receiver. This is obviously an unsuitable location to take a temperature reading, si the room created for the wired TadoX wilk have its temperature meaured by the smart radiator valve located there This configuration will mean that the Wired TadoX stat acts only as a receiver, but does not act on its own temperatue measurement device. Using a wired TadoX thermostat overcomes the limitation of a single wireless receiver X in any 'Home' installation.

Note you can switch which zone valve gets the wireless receiver. It may be convenient to connect the wired TadoX to the UFH zone valve directly, if this valve and its salus receiver happens to be convenient the to location of the UFH area. This would allow the radiators' zone valve salus receiver to be replaced with the TadoX receiver, while the TadoX wireless thermostat could be placed in the same place as the current Salus for radiators. Finally, if you position a wired or wireless thermostat in a room which also has a TRV, you should assign the thermostat as the measuring device for that TRV, as the thermostat will have a better read of average room temperature than the sensor on the radiator valve. This prevents having two devices conflicting over the temperature in the same room.

I hope this makes sense to you, but you just need two relay devices to electrically power the two zone valves, which in turn jointly fire the boiler via the zone valves internal relays. Two wired thermostats or one wired and one wireless fit the bill. There is no seperate TadoX radiator receiver that I am aware of. This is just either a wired stat or a wireless stat's receiver configured as the Zone controller for any TRV

Yes, a wireless sensor can use a wired stat, the wireless receiver, or act as the measuring device for a TRV (which in turn calls the boiler via a wired stat or the receiver also known as the Extension Kit). Its fairly versatile. Here I have a sensor or wireless stat, acting as a temperature measuring sensor for the same room TRV, which together trigger the boiler via the relay in the wired stat.

As there are no zone valves in the legacy plumbing, and there were no TRV valve heads on the rads, I converted just three to TRVs to give some finer control. Fitting these required changing the radiator valve to a TRV pin valve, a fiddly bit of plumbing, and a fair extra expense in addition to the smart hesds if you're considering a full radiator smart TRV upgrade and you can't DIY. I done just three, master bed, kitchen and main lounge. The lounge a particular success, coupled to a new larger high output radiator, it means it can be heated rapidly, but sparingly, only when needed. Kitchen can be heated only when needed, master bed needed its own means to call the heat, but herself couldn't stand the valve motor noise in the early hours as it topped up the heat, so cooler but quiter is the outcome. Pay the price for being a technophobe (and spoiling my fun!).