Help connecting wireless thermostat to boiler (2023 Update)

[AnthonyL]

A long version of the installation is in my recent thread " Turning radiator off/down - no thermostat valve"

Simply, Baxi 105 HE Combi installed at the end of a utility room extension.

11 radiators in a bungalow, all but two have TRVs.

Intending to just about fully turn off the radiator in the hall which has no TRV and is mainly heating empty space.

Not practical to wire thermostat to boiler so wireless needed.

If going this far would probably want to control by day/hr easily but do not need zoning as TRV's should handle this.

I have a BT hub/router with ethernet outlets but it is not convenient to run ethernet cabling any distance though it is on a small cabinet which can hold a couple of devices.

At the moment I am looking at:

1) Putting the thermostat in the bathroom (radiator has no valves).

As door is opened the rad is to the right and the sink unit to the left. Thermostat to go behind the door and to the left of sink unit

Boiler is ~20m and a couple of walls away from bathroom.

2) Getting Boiler is on the back wall and within a frame hardboard cupboard. It would be convenient to have the receiver unit to the left mounted on the hardboard and so convenient to control panel. It would be about 8" away from the boiler. It could go to the outside of the cupboard but untidy.

In the future I might want remote access but at the moment it will be a massive improvement on my current procedure of setting the timer clock and temperature controls manually.

What can go wrong? Or am I on the right track?

PS Instructions as to where to fit the controller are on the boiler control panel and the 240v input/output which are currently interconnected will go through the controller.

[alan_m]

Why?

You need the thermostat to make where you occupy most most comfortable. Personally I have my thermostat in the room used every evening for watching TV etc.

[Brian Gaff]

Also I think in today's world you need to make sure both devices can use the

5gig band, as interference on the lower one is very likely. Brian

[Brian]

I’d recommend the Hive system. It isn’t the cheapest but it is established, the user interface is very good. I find the remote access excellent.

If your existing controller uses an MK14 back plate ( the plate the controller clips to), installation is very easy - you may not need any wiring changes.

We already had normal TRVs so I didn’t change to hive ones - especially as we don’t use some rooms and just set them low.

I used the data from the Hive app to adjust the on/off times for the heating. I was surprised how early in the evening I could set the heating to turn of yet maintain the room temp, although the house is well insulated.

[AnthonyL]

[alan_m]

On a new system you would select the optimum place for the thermostat (possibly you main living room) and not fit a TVR in that room. The bathroom may not have had a TVR as a safety mechanism - somewhere for the pump to push the water when all the TVRs in the system shut off.

Just because your bathroom is currently the only room without a TVR it doesn't mean that it is the best place for the room thermostat. I doubt if anyone reading this has the room thermostat in their bathroom - for good reason.

The advice is correct in that the room heat should not be controlled by both the room thermostat and a TVR BUT you are possibly drawing the wrong conclusion about locating the room thermostat. Fit the thermostat, say, in your main living room and replace the the TRV with a normal lockshield valve. Rather than removing the TVR you could just unscrew the TVR head which leaves the valve fully open (just make sure that the valve controlling pin that you can see when the head is removed is free to move and not stuck - it will be stiff so just lay the flat of a spanner or body of a pair of pliers on the pin and press down fairly hard and release. The pin should remain in the fully up position)).

 The valve with the head removed may not look cosmetically good but it will do the same job, in this instance, as a replacement lockshield valve. If you have a decorators cap for the TVR you could drill a small hole in the top of so it doesn't depress the pin and then use this modified cap to give a good cosmetic appearance.

See

[AnthonyL]

The main living room, which is a large "L" shaped lounge + dining, has

3 radiators.

But are you in effect saying that the thermostat is acting as the TRV, ie effectively replacing it? That makes sense I guess.

[The Natural Philosopher]

No, its rules for fools, and guidance for wise men.

The point is not to have to call for heat in a room in which someone has shut the radiator off.

Just consider what will happen in a room with a radiator thermostat set for 15°C and the radio stat is set to 19°C.

[AnthonyL]

Ah - the lounge is the room that will always have rad stats on max :)

[The Natural Philosopher]

That will work.

[ARW]

Might not:-;

I once attended a call out where the customer placed the wireless stat on the radiator......

But yes it should work. If the TRVs are fully open then the stat should do it's job.

[Brian]

Sounds right to me.

We have the thermostat in the hall, the rads there don’t have TRVs.

Originally, the thermostat was in the sitting room and we didn’t have TRVs or Hive.

Having a thermostat in a hall is quite common.

[AnthonyL]

I'm a bit new to all this new fangled stuff but ....

I think I'm get it.

[AnthonyL]

That would have been the natural choice for me except I've now decided that heating the hall, which is a full room size, is an extravagance with costs going up the way they are. This whole exercise started (see other thread) with my conclusion that the hall radiator, which has no valves, needs to be switched off.

The main downside is the change in temperature traversing from front of house (living quarters) to back of house (sleeping quarters and study).

Just need to be disciplined in keeping doors shut.

[Brian]

I suspect that, with, Smart TRVs, you could ( for example) avoid heating the bedrooms during the day (assuming they are unused), give them a burst in the evening and morning ( if that is what you like), and apply a similar approach in other rooms where the use is predictable. The problem is where to put the thermostat - it shouldn’t be in a room with TRVs ideally. I don’t think it is a hard and fast rule - you may be able to make it work by ‘clever’ programming of the TRVs.

[alan_m]

The advantage of having a wireless thermostat is that you can move the transmitter around and you can experiment with it in the hall or in your living room.

Where people place the thermostat may depend on how many people in the house and how many rooms being used a lot of time for living. If there are only one or two of you and normally spend most of your leisure time in one room then that is possibly the ideal location. In my house one room is heated to an elevated temperature (20 to 22C) and the rest of the house controlled by TVRs and kept to maybe 16 to 18C (bedrooms a bit cooler)

This whole exercise started

Pedant mode: it will have two values but probably require a spanner to close them one of them to the off position.

Yes, this is probably the way to cut costs. Definitely close doors to rooms that you don't use much. Close the door in the room where you need keep in most heat.

[SteveW]

I'd not put the thermostat in the living room - normally it'd go in the hall, so that it can control the temperature without interference, say from people turning a fire on.

In my own house, I have a thermostat and a motorised valve for each room, so it doesn't matter if someone puts a fire on; the sun happens to be shining on that side of the house; we're cooking, etc. Each room will get up to the temperature set for that room, at that time of day, and then shut off, unless it cools again. None of the other rooms are affected.

[John Rumm]

So in that case you would set all three TRVs to max temp, or remove their heads.

It replaces it, in the sense that when the room reaches your preferred temp it will turn off the heat. The difference is that it will do it for all of the heating, and not just that room.

[John Rumm]

Yup if you have a room that is not used, turn down its TRV and shut the door on it. It will stay cooler / cold compared to the rest of the house.

[Tricky Dicky]

I have the Hive system and have the Hive thermostats on all radiators except the bathroom which is the official bypass for the CH system. Despite the advice not to install the thermostat in a room with a TRV the thermostat is in the lounge which has a single TRV controlled radiator, I have found no issues with the setup. The smart TRVs are not like normal TRVs in that they can operate heat on demand. So if the lounge TRV demands heat it overrides any setting on the main thermostat, likewise if the TRV senses the temperature is adequate it will shut off the radiator immaterial of the main thermostat settings. The beauty of the smart TRVs is you can literally heat as many rooms as required or simply one room.

There are other smart systems that do a similar thing, I am quite pleased with the Hive system.

Richard