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!).

I'm assuming there is already a 16 input wiring centre, which is used to combine the stat calls into a single call to the heat pump, while each stat individually opens its Rehau hub valve to that stats area. This is the purpose of the wiring centre, otherwise if you just join all stats' switched lives together to fire the HP, and stat wull then open thr valves to all UFH zones.

All you will need to do to group the 18 into 4 groups is pick one stat from each group to be the master, and bridge that at the controller to all the valves in its domain. Say you have 5 seperate stats in 5 bedrooms, you just pick a master stst to manage heating for them all, and remove the others. Similarly with reception areas, offices and studies, halls, and landings. 4 might be a bit broad, two 4s and two 5s. 6 stats would give an average if 3 UFH zones combined.

As your current stats are mains powered, you can replace these with other brands of connected stats which can take power from the mains. Heatmiser wired Neostats which can operate as individual programmable thermostat/timers can be coupled to a the Neohub gateway to give app control of operation and programming, with some smart features such as Homelit access. Their programming like the EPH is fairly basic last time I looked, but they are robust and reliable, and being mains powered require no battery support. Stats cost about €85 each, the Neohub is about €200.

You can also consider wireless stats, which if consolidating multiple UFH zones gives you the flexibility to move the stat for those grouped zones into an optional compromise location, or even placed on a stand to move around. Some stat kits with the receiver relay are little more than the cost of a wired stat. Hive mini plus receiver relay is about €99. The receiver can be mounted and powered back at the wiring centre or in place of the danfoss. The wireless stat to this receiver can be located anywhere in the general area of the combined zones it controls. The receiver will be connected to operate as many of the UHF zones valves as you wish to join by just bridging the stat inputs for that group to the switched live out of the receiver.

Just to avoid confusion, when you say Rehau hub, you are referring to the valve actuators on the flow amd return manifold, these;

The term hub is generally looslely used for the interface between thermostats and the Internet, but each manufacturer often use their own, hub, hubR, bridge etc. The wiring centre essential for thr circuit heavy cintril of UFH migh also be be referrred to a wiring hib or a lex boc.

Are there 18 of these actuators spread over a number of manifolds, and are there 18 seperate UFH connections. Is there a single wiring centre box for all 18 thermostats, or is the system split into a number of wiring centres. Is it possible even that some thermostats are just crossed connected with each other, opening the same actuators? If you want the simplest way of doing this and reducing the number of stats, you'll just need to identify each stat's switched live entry to the wiring centre, and cross connect those you wish to group, abd remove all bar one of the grouped thermostats, replacing that one with a smart wired stat if your choice. The actuators generally have a pilot lamp so should be easy to log which stat opens which manifold actuator. Rewiring a new wiring centre and mapping all the connections out to various pumps and possibly motorised valves will make a big task of what could be simple, even incremental. You could start by simply replacing one Danfoss stats with a TadoX wired starter kit (Stat and Internet bridge/ border router). Use this to gain app control of the most important zone, and take it from there.