Temperature inaccurate on TRV's
When the heating is off, The temp shown by the TRV's is pretty accurate and close to an independent thermostat placed close by. However when the heating is on and hot water is flowing to the radiator the temp shown is almost 3 degrees higher than what the independent thermostat shows. Its as if the heat from the pipes etc screws the temp reading.
I realise you can set an offset but when the heating off, this means the temp shown is much colder than what it is.
Has anyone else experienced this ?
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@Sherlock The air by the radiator and the valve is obviously going to warm up faster than the air elsewhere in the room. Then there's convection and drafts moving that air around. Also hot air rises, so a temperature reading taken high up on the wall will not be the same as one taken on the floor. The TRV might be in a draft, or a cosy sheltered spot.
You can't really expect the entire room to be the same temperature as the TRV, especially if the heat has only recently turned on and is yet to permeate every crevice of the room, the walls, the furnishings. Obviously the TRV can only report on its own condition - not every other part of a room, especially a large one, possibly influenced by open doors or windows etc etc.. Radiator size also factors in. If the radiator is too small for the room it could be scorching, but the room as a whole won't be that warm.
If the TRV measurement does not suit your needs (assuming it is at least reading its own temperature accurately) then this is where a wireless temperature sensor comes into play. Put it where you like and control the room heating with that instead of the TRV temperature reading. Or just adjust the target temperature up by a couple of degrees until the temperature is as you wish, where you wish.
FWIW I do have wireless temperature sensors strategically positioned in each room to monitor comfort levels where it matters rather than by the TRVs. They aren't Tado sensors and they exercise no control over the system. They are Bluetooth thermometers that let me check the whole house from an app. Taking my lounge as an example, here are the readings right now from Tado vs my independent thermometer.
I have to say that the TRV readings work well enough for me. If there is a problem with comfort then I simply adjust target temperature to suit. By the way, the high reading from the Bluetooth thermometer is from yesterday when we had a three hour power cut, with no boiler, and had to use the gas fire in the lounge, which we normally never use. The thermometer is directly above the fire. No surprise that it reads a little high.
EDIT : p.s. I also have some other simple thermometers, with thermocouple leads to place exactly where I wish, checking temperatures throughout the house. This is the one in the lounge right now. Happy days! :-)
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There are many discussion threads on this well-known subject, with a variety of suggested solutions. Use the search box to find them and read through all the opinions.
One of the popular ways round this is to have a separate wireless thermostat, or separate smart radiator thermostat, in the centre of the room, linked to the one on the radiator. However this is expensive and impractical for every room.
The offset does help, to a point, and with some adjustment of the "off" temperature in the room can work fairly well to achieve a more realistic room temperature when the heating is on.
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Someone once suggested Oventrop 1011450 adapters to turn the TRV through 90 degrees. Any further thoughts on these?
Anyone tried fitting some sort of heat shield between the radiator and the TRV?
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I think i've read before that EU-style TRVs that stick out horizontally from the top of the radiator give a more accurate reading, though as in the UK they always seem to be vertically at the bottom this would require a fair bit of work to replumb.
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I notice that some of mine are more affected by the temperature of the rad than others. My old fashioned double rads with a wide gap in between leave more room between the rad and the TRV and work best. The modern ones with closed sides place the TRV much close to the rad and struggle to anything sensible. I'm either going to buy Oventrops or put a heatshield between. Just wondering what anyone else may have done.
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Can't believe that there are years of complaints on here about TRVs reflecting radiator temperature rather than room temperature and that no-one has experimented with heat shields.
When I have the time I'll be trying some options and hopefully feeding back results.
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@Folkranger did you have a chance to play with that? I'm also considering this approach.
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Yes, most of my radiators are in radiator cabinets, which does not help with reading accurate room temperature. I have made simple heat shields for these by glueing aluminium foil onto board. The width of the radiator and about 30cm high with a slot that allows it to sit over the union between the rad and the TRV.
Did it make a measurable difference t- I don't think so.
In fact, without these, the room temeratures are very accurately brought to match the set temperature. My issue with this is that the TRV must get heated to temp. before the room and will hunt (on and off) while it brings the room to temperature, thereby taking longer to achieve it's objective.
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