Replacing wall stat with wireless?

... I did try in different positions. It would seem heat goes up from radiator along ceiling down the far wall and along floor back to radiator, so opposite wall works well, on a table in front of radiator also worked well ....
Yes, that makes sense, but the heat is not going to rise from the radiator in an an infinitely thin column - so I would have expected (perhaps wrongly!) that sensing temperature only an inch or three from the radiator would have the sensor in the column of rising hot air.
So reasonably low down as side of radiator likely has both return air travelling along the floor to compensate for radiated heat from the radiator.
Yes, but that 'returning air' will probably be fairly close to "room temp", so mixing that with much hotter air should still end up with the air being sensed being appreciably hotter than the room.[/QUOTE]

Kind Regards, John
 
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I thought thermostats should ideally be placed at a height of five feet on an empty(ish) wall away from direct sources of heat.

Obviously they won't work as well if put in a drawer.
I seem to remember it is one of the building regulation documents, 1400 mm from finished floor level as below that you can't read display and above you can't reach in a wheel chair, which is really a bit silly as a wheel chair user could not read it at 1400 mm but a non wheel chair user could bend down, however it's not at that height so it works correct it is at that height for access.

With living room over heating I actually placed 5 thermostats around the room, all around 4 foot high, I was measuring 10°C some times between the thermostats, switching on a fan would bring them all to same reading, but sun through the windows would give hot spots in the room.

This has been the subject for debate on the use of fan assisted radiators, if you circulate the air past a cold wall or window it can cool the whole room, but if are only circulates by convection you can leave cool air by windows but have warm air where the chairs are. Of course this will not work is radiator is in the window. I have never worked out why in one room the radiator is on an internal wall, and other room under a window when it needed extra pipe work and loads of bends to place it there? Same sized rooms same size radiators but one under window that room was always cooler until electronic TRV heads were fitted. Upstairs the reverse, above room with radiator in window bedroom has radiator on the inside wall, and other two bedrooms radiators in the window.

OK today with double glazing should not be a problem, however we have glass that lets suns rays in but does not allow them out, sure glass have been fitted wrong way around? Seems you can get a film that sticks on the glass to reduce heat from sun.

So a Myson fan assisted radiator will heat whole room even, I know I had one in last house, but question is do you want room heated even?
 
I was measuring 10°C some times between the thermostats

I don’t doubt it. But, for me, I don’t really care what number it says on the stat – as long as I can relate that to how the room feels, and it’s consistent from one day to the next, I know where to set it to feel comfortable. So, for example, if I mount it on the wall, and find I have to set it to 23, and that makes where I sit feel the same as when I put it on the coffee table and set it at 19, that’s fine – wherever it goes, it’ll stay there…

I have never worked out why in one room the radiator is on an internal wall, and other room under a window when it needed extra pipe work and loads of bends to place it there?

In my cynical old age, I’ve learned a governing principle of the universe – when in doubt, it’s money. Someone, somewhere will have discovered that potential house buyers prefer the look of rads under windows, or whatever :confused:
 
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In my cynical old age, I’ve learned a governing principle of the universe – when in doubt, it’s money. Someone, somewhere will have discovered that potential house buyers prefer the look of rads under windows, or whatever :confused:
I don't pretend to fully understand (or having spent enough time thinking about it to understand) the physics of heating a room with a 'radiator' (which heats mainly by convection, anyway!) but, again speaking from relative old age, I was brought up to believe that 'under windows' was where radiators should be located (admittedly in the days when no-one had even hear of double glazing!).

I don't know what is the current ('informed expert') advice about the positioning of 'radiators'.

Kind Regards, John
 
I have often seen radiators fitted under windows, I assume as furniture is unlikely to cover them, I have never seen a coal fire under a window, and I know many a coal fire was poorly planned, there needs to be a air supply to a coal fire, so on the outside wall allows vents to allow combustion air into room to feed fire without causing drafts, however houses have been built with flues going up centre of house without any ducts to bring in combustion air, it would seem builders have not got a clue how to heat a house and have never had throughout the ages.

DSC_2921_2.jpg

Here they have not even got a roof on the house, don't think underfloor heating has ever worked?

If a room is held at a set temperature it really does not matter where the thermostat is, Roger465 is correct, we can compensate for the difference between where measured and where we sit. As long as the heating is analogue controlled with a TRV and modulated boiler flame the place where thermostat is placed does not matter.

However with digital control this changes, hysteresis is the problem, there has to be a difference between on and off temperatures, so when the thermostat switches on, there is a delay before the heat produced reaches the thermostat to turn it off, if the delay is too short, we loose energy through the flue every time the boiler switches off, so it costs more, if the delay is too long, the heat in the room is likely to over shoot. So it is really important where an digital thermostat is positioned.

However the big question, does the digital thermostat control room temperature? or is it to reduce cycling? there is a problem using return water temperature to control a boiler, the boiler needs to fire up and circulate water even on a hot day to find if any heat is required, so fitting a thermostat that switches off the boiler on a warm day is a good idea, to do this it needs to be in a room normally kept cool, so the off temperature can be set low, when it is 20°C outside we don't want central heating to run, so the thermostat needs to be set less than 20°C yet in the living room we often want it at or warmer than 20°C so living room not suitable for the thermostat to stop cycling.

So with in my case Bosch Worcester Wave thermostat will likely control the room it is fitted in A1 where ever it is located, however the instructions say more than 500 mm from ceiling and more than 1200 mm from floor and 1000 mm from door in the reference room. This reference room clearly always needs heating, and there are also EMC considerations as to location.

A reference room is an area (for example the hallway or landing) in which the temperature is measured, which is representative of the whole home and where the most time is spent.

Personally I don't spend most of my time in the hallway or landing, and because the sun effects the temperature of our living room it is not representative of the whole home. I did a find on the installation document for TRV it does not refer to them, however I would assume one is not fitted to reference room?

So although a Wave thermostat is designed to fit my boiler and I would expect if fitted in living room would keep the temperature spot on modulating the boiler through the EMS bus as required, the question is what happens to the rest of the house? I would prefer EvoHome where it takes multi reference points to decide how to modulate the boiler, but Bosch Worcester is not OpenTherm. Also the thread asks about wireless and Bosch Worcester Wave is not wireless. Although it does connect to internet if required.
 
Still waiting for the wireless stat to arrive, as eBay have cocked it up... in the meantime, naive question - when a TRV is turned up as far as possible, is it always on, ie permitting full flow no matter how hot the room gets?

Thanks :D
 
... in the meantime, naive question - when a TRV is turned up as far as possible, is it always on, ie permitting full flow no matter how hot the room gets?
In practice, probably yes, but it obviously depends upon the highest temp to which it can be set and the capability of the heating system to raise the temp - if the heating system can heat the room to, or beyond, the maximum temperature the stat can be set to, then the stat will start turning down/off the flow to the radiator.

Kind Regards, John
 
Just in case any other poor sap does a search on wireless thermostats and wonders what happened here, well… nearly a year on, and I’m very happy with the Salus jobbie.

Fitting the receiver was a doddle, once somebody had pointed out on here what I HOPE I would have noticed myself, ie that the “electrician” who fitted the original stat had used green/yellow earth wire to connect the switched live – apart from that, it’s just 3 wires and 2 screws.

The transmitter is sitting beside me on its little stand as I write, showing 21 degrees; if I want to nudge it up or down, I just reach my hand out, then hear a click up the hall where the receiver is. Honestly, I wish I had done this years ago. Only quibble is that said little stand annoyingly falls off the back of the stat if you move it.

An added advantage is that, if you like, you can take it to bed with you, and set the temp you want it to be in there when you wake up in the morning.

And no sign of the batteries dying yet.
 

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