Boiler Relay Wireless Range

[Harry Bloomfield]

The wheel is old tech compared to hover craft and maglev.

..and each is better suited to different situations and uses. Horses for courses.

 

[stem]

I don't agree with that

Can't see why, it's basic physics.

1. If the temperature set on the TRV is reached before the room thermostat setting, the TRV will start to close the radiator down, the room thermostat will not be satisfied and the boiler will run continually wasting energy, and not provide a working boiler interlock as per the building regulations.

2. If the room thermostat switches off before the TRV, the TRV becomes redundant and serves no useful purpose. If there is one there already to stop it interfering with the room thermostat...

you can simply set the TRV(s) to max in that room, or remove the head(s).

3. It's also messy. If you are in a room that you are finding too warm or too cold, what do you adjust? the room thermostat? the TRV? Both? I also find that while most householders understand and operate their heating controls properly, many don't and would fail to operate such a set up successfully.

4. Manufacturers recommendations:

Energenie MiHome

Hive

Even if you were to try and have both and set them to the exact same temperature, they are not 'identical'. Apart from them sensing different parts of the room, the work differently, one is an analogue device and other other is digital, just on/off.

 

[Harry Bloomfield]

3. It's also messy. If you are in a room that you are finding too warm or too cold, what do you adjust? the room thermostat? the TRV? Both? I also find that while most householders understand and operate their heating controls properly, many don't and would fail to operate such a set up successfully.

Well obviously as I said, you leave the TRV alone and adjust the stat.

Even if you were to try and have both and set them to the exact same temperature, they are not 'identical'. Apart from them sensing different parts of the room, the work differently, one is an analogue device and other other is digital, just on/off.

Modern gas boilers are not simply on or off - with a decent control system they can modulate their heat output to much better match the demand for heat.

 

[stem]

Modern gas boilers are not simply on or off - with a decent control system they can modulate their heat output to much better match the demand for heat.

Quite right of course, but unless I'm mistaken, the thermostat the OP is looking to replace is just on/off, as is the one he's thinking of replacing it with. Can't see any reference to the boiler as to whether its suitable for OT etc., or whether it's being controlled by motorised valve(s)

 

[ericmark]

With a standard TRV set on the *123456 scale at around 2.5 it starts closing at 18°C but not fully closed until 22°C so with a wall thermostat set to 20°C it delays the switching off long enough for other rooms to catch up.

Yes if we have the imaginary room with no windows to catch the sun, no alternative heating, and no outside door, which is normally kept cool, then no TRV will work, but that room never really exists, a living room is not kept cool so as winter turns to summer the central heating will come on in the morning but by afternoon want the AC running. So looking for a room kept at no more than 18°C.

Most houses only room if you can call is a room kept at that temperature is the hall, and since it has an outside door, recovery time is important, so the TRV allows the radiator to heat the hall to 16°C rapid, then slows down the heating allowing rest of house to heat up.

the room thermostat will not be satisfied and the boiler will run continually wasting energy

That may be true with a non modulating boiler, but with a modulating boiler the boiler will auto turn down output until at its minimum, at which point it will start to cycle, the anti-cycle software will increase the space time if when it fires up water returns hot, and because the boiler has switched off, when it turns back on it does so at minimum output, if an external device turns it off then it turns back on at maximum output.

So turning the modulating boiler on/off continually wastes energy all the on/off thermostat needs to do is switch off the boiler in summer. Unless very old gas boiler or an oil boiler.

 

[George Costacovich]

Thanks all, lots of food for thought there.

This is a bit of strange house, actually two terraced Victorian stone cottages that have been combined, though one was end of terrace and has an extension with a big open plan space.
This is the room which is often cold and has a three panel bifold at one end going into the garden. It would have been a good candidate for underfloor heating.

As has been noted, there are likely not enough rads in this room and we are considering putting some large vertical rads either side of the bifolds where it's coolest.

The lead rad with no TRV is in the hall opposite the current Siemens thermostat, though the hall itself is quite compact and not draughty. That rad also possibly contributes to the floor above being normally quite warm, so all the TRVs on the first floor are on quite low.

Though I do understand the thinking behind where the thermostat should be, to me it makes little sense for it to be in the hall which where we spend the least time.

The higgeldy-piggedly nature of the house would likely be a good candidate for an Evohome or other system with a number of smart stats if it wasn't for all the stone walls making Wifi coverage tricky.

Just to add to the fun there are two combi boilers and two gas meters, so the two cottages essentially retain there separate heating arrangements.

The combi which serves the room with big plan open space is a Worcester Greenstar 37CDI fitted in late 2007. though the previous owners had one of those BG maintenance contracts and say it got almost completely rebuilt by them quite recently. Would this be suitable for Open Therm or any newer system?

 

[stem]

it makes little sense for it to be in the hall which where we spend the least time.

That doesn't really matter that you don't spend time in there, the thermostat controls the whole heating system [or half of it in your case ] so it needs to be in the best place for the whole system. If it's in the last area to warm up, TRV's in the rest of the property control the comfort in the areas where you do spend your time. The hall is generally chosen as it best fits the criteria in that for most homes it doesn't get warmed by sunlight, cooking appliances, open fires / woodburners, or even people. [Although I guess parties are not really appropriate at the moment ]

But it's your house, of course you can put it where you like. But if it's in an area cooler than the hall, the heating will stay on much longer and so the hall radiator will need a TRV to stop it overheating.

I'm sure one of our WB experts will be along shortly to confirm it's suitability for OT or not.

 

[Harry Bloomfield]

Though I do understand the thinking behind where the thermostat should be, to me it makes little sense for it to be in the hall which where we spend the least time.

That isn't the point at all of the thermostat location. The chosen location needs to be representative of the general house temperature as a whole and containing a rad without a TRV. The hall gets a mix of temperature feedback from the rest of the house and its own rad. So if the hall is cool, it is safe to assume the rest of the house needs some heat input. The TRV's on each other radiator, in their separate rooms, limit those room temperatures and the limit need not be the same as the thermostat.

My original wired thermostat was installed on my orders, so it could be in the in the hall, or the installer own idea of where it ought to be - in the living room. That worked well for the living room, but the rest of the house could be too hot or too cold. I quickly moved it to where I thought it would best work, in the hall.

I have since upgraded my boiler a couple of times and the controls too, but the thermostat remains where it belongs in the hall. Even that is a bit of a compromise...

Open the front door, let the cold air in and the boiler fires up to compensate, luckily we tend not to use the front door that much, we generally use the more convenient side door. When lots of cooking in the kitchen, the heat from the kitchen escapes into the hall, with the result that the heat for the rest of the house goes off - then I simply transfer the wireless stat to the living room.

We tend to have the stat set at 18C when it is in the hall, which is cooler anyway, individual rooms are warmer when their doors are closed.

 

[BlueLoo]

No need to rely on zone stats these days.
The world has moved on.

 

[Harry Bloomfield]

No need to rely on zone stats these days.
The world has moved on.

You can repeat that as often as you like, but it will make little difference. What works and works very well indeed, is all that in most cases is needed, until there is a step change in technology.

 

[BlueLoo]

You can repeat that as often as you like, but it will make little difference.

Well to you, who likes to heat his whole house with all the doors open, no probably not.

To those who are a bit more carbon (or cash) conscious, or prefer not to rely on a stat in a cold and draughty hall to keep them warm I'd say the opposite.

Get with the now, Grandad.

 

[Harry Bloomfield]

Well to you, who likes to heat his whole house with all the doors open, no probably not.

To those who are a bit more carbon (or cash) conscious, or prefer not to rely on a stat in a cold and draughty hall to keep them warm I'd say the opposite.

Get with the now, Grandad.

Yet another clueless and misinformed idiot, coming on a forum spreading his pointless, entirely unnecessary ideas to spend someone else's money. In the box you go..