Does this seem right for a room thermostat?

[CBW]

Whenever I’ve looked at manufacturers instructions for sitting of a room thermostat and @stem ’s written instruction for siting of a room stat, my current setup seems illogical, yet when I look in the mi’s it states it’s ok? Very confusing information.

Room stat: Myson MRT1
Location: open plan living room, which incorporates dining room/kitchen.
Number of rads in this location: x3 with TRV’s

Will I get big swings or will it be ok? Whenever I’m upstairs or in the downstairs toilet it seems very cold, although bathroom is possibly a good heated room.

 

[ianmcd]

No you cant have a room thermostat above a radiator and it should be installed in a space with a radiator with no TRV on, and before all you google warriors jump in about my next statement just read that this is MY opinion and nothing to do with any Part L, Boiler plus or any of the other shoite that we have to adhere to, I totally disagree with the need for a room thermostat, it is a boiler interlock yes and adheres to some code, if a house has TRVs the room thermostat will over ride these, modern mobile thermostats can be moved around with you wherever you are sitting, Adheres to code because it is a boiler interlock, what it actually is a remote control for your heating with a temp display on so make s a complete mockery of the supposed codes, but in effect is far more suitable for the user, I have a Hive in my house and TRVs on every rad, I dont use the thermostat part of the hive and just use it as an on/off switch with my phone, I dont need to ask the local airport if it is cold outside, I know when it is cold, I have the TRVs set to what I want them to be at, and guess what , it all works no problem, I just hide when the room thermostat Police come around

 

[stem]

Number of rads in this location: x3 with TRV’s.

If that represents all of the radiators in the same area, that's basic installation error. There should be at least one radiator without a TRV in the area where the room thermostat is located. Otherwise the TRV's will interfere with the correct operation of the room stat.

Consider a scenario: The TRV's are set to 20 degrees, room stat set to 22 degrees, the TRV's will stop the room temperature getting above 20 degrees and the room stat will never switch off, so it might as well not be there and the heating will run on indefinitely even though not really required and wasting energy because the temperature set on the room thermostat will never be reached.

The bottom line is that the room thermostat turns off all of the radiators when the set temperature in the area where it is located is reached. So, it should be one of the last places to get warm, then the other rooms are warmed first before the room thermostat turns off all of the radiators.

Sometimes there isn't a perfect position, my mothers bungalow had an internal hallway without a radiator, that had no external walls so was always warm. The lounge had a gas fire in it that was sometimes used. The kitchen was a non starter because of the cooking heat, and the bedrooms she always liked really cool, so if it was in there and set at the temperature she liked, the heating in the rest of the house would been cold.

As I said in my other post, I installed a smaller radiator in my hall where the thermostat is located making it the last room to heat up and now it works perfectly.

 

[oldbuffer]

1. If you have TRVs on radiators in the room with the room thermostat, turn all the TRVs to maximum, and then the room thermostat controls the temperature of the room.
2. I don't see any contradiction in the Myson instructions. It suggests "on a wall ADJACENT to the wall with the radiator", and specifically states not exposed to radiator (or other) heat sources.

 

[CBW]

If that represents all of the radiators in the same area, that's basic installation error.

Sometimes there isn't a perfect position, my mothers bungalow had an internal hallway without a radiator, that had no external walls so was always warm.

I didn't install it, it was done as per new build. As for the "hallway" it's not big so maybe that's why it's in the lounge? Also I can only see x2 wires must just be a switch

 

[ianmcd]

Also I can only see x2 wires must just be a switch

All thermostats are just a switch

 

[stem]

1. If you have TRVs on radiators in the room with the room thermostat, turn all the TRVs to maximum, and then the room thermostat controls the temperature of the room.

That would work, until someone fiddles with it or turns it off during the summer. I've been called out a few times to look at a 'broken room stat' and someone (or the kids / dog etc.) has moved a TRV from the max setting

I didn't install it, it was done as per new build.

I didn't say you did . But someone did. If it's still a new build, get the builder back to rectify his schoolboy error.

 

[bernardgreen]

All thermostats are just a switch

But a switch needs someone or something to operate it.

Also I can only see x2 wires must just be a switch

In your case it almost certainly is "just a switch" but two wires can be a data bus.

 

[ianmcd]

In your case it almost certainly is "just a switch" but two wires can be a data bus.

You just cant help yourself from trying to appear like a smart ass, in his case it definately is, it is a Myson MRT1, this can not be used as a data bus

 

[CBW]

If it's still a new build, get the builder back to rectify his schoolboy error.

It was a new build ten years ago, I contacted Myson at the time as I thought it was in an odd location, and they said it was fine and would work - although they didn’t suggest setting TRVs on max. It was installed by either a heating company or electrician. We had several issues with the programmer as well, I think we’re on our 4th and seems to be ok. One of the issues was if we boosted the heating or hot water, or both together if one became satisfied it would also knock the other one off, very strange behaviour, but as I say seems ok now.

 

[bernardgreen]

You just cant help yourself from trying to appear like a smart ass, in his case it definately is, it is a Myson MRT1, this can not be used as a data bus

As I said in this case it IS just a switch but it is not sensible to assume that "just two wires" will always connect to " just a switch"

 

[ianmcd]

Bernard, people come on here for an answer to a specific problem, not to hear you ramble on absolute tosh about stuff completely unrelated to what they are asking, please if you can offer constructive advice then do so, but stop trying to be smart and come up with absolute drivel to confuse people, and you think it makes you seem intelligent, it does the complete opposite