There's nothing planned about the traffic lights I have any interactions with 
Improving on TRV
- Thread starter sophiecentaur
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So you felt insulted by the fact that, not knowing anything about you, your qualifications or your experience, I asked for some evidence to cover your statement. Would you take something I told you without evidence? (clearly not) If you read all the posts in this thread (no - I wouldn't wish that on my worst enemy) you will find a lot of misinformation, along with the good stuff. now, you may be in a position to sort out which is which but I am not, which is why I started the thread. That's what I meant by 'empathy'; making your answers fit the question in order to help someone through unfamiliar territory. Why else did you even contribute to the thread?
Instead of suggesting somewhere specific I could look for evidence to back up your statements, you got ratty. Why? A single reference (I assume you can do that?) would have sorted me out and I would have been able to make progress. I took on board the fact that TRVs respond mainly to room air temperature as soon as an actual figure was quoted. But, by them you had decided that I was just being a smartarse who wouldn't listen. You will notice that there is actually no agreement here between contributors about the true definition and consequence of 'response time' but maybe you have your own view. Which view should I take, if no one is quoting some authoritative source on the subject of actually controlling room temperatures? Why should I blindly take yours over someone else's? I know (and so do you) of some totally useless heating engineers, whose advice would be better to avoid. How am I supposed to know who is or is not useless - unless they can quote some hard info?
Why get so stroppy all the time when all I want is some source of good facts and not to be shouted at because of that? You don't like my 'style'; I don't think you should have to like it as long as you understand what I am saying. You feel insulted because I don't blindly accept what you claim and I fell insulted by you for dismissing my approach as rubbish. Try this wiki link. It is an introduction into general control theory and it applies everywhere, even to the system you installed the other week. Or try this link, which is pretty much the works. This more or less describes what I have been trying to say. You may say it's all baloney but it is the way things will be going, once systems are cheap enough.
I'm going to shoot a Salus room stat with an air rifle because I'm that bored with this crap! Video soon!
I'm peeing blood again so I'm going to bed soon.
Video didn't bloody record but a quick 4 shots 2 dead centre and a couple for practice! It's now 3 degrees more accurate and still just as reliable! Its surprisingly sturdy with a bit of body armour in the centre! It's a stat I would choose to survive a shooting. Still crap for your heating requirements
though.
I do have a little sympathy for some of the things you are saying.
But that rather evaporates when I have tried to explain that "response time" for TRVs mean nothing without a definition and anyone can choose their own. But you do not seem to have taken that on board.
I even mentioned the typical engineering values often used of 10% to 90% !
Tony
We need a better Response time from you next time or you are fired!8 fecking pages on a TRV. I despair FFS
But with all due respect Tony, a TRV sitting close to double radiators for example, there is a lot of heat emitted both sideways and upwards, and this immediate heat is far more overwhelmingly stronger (or higher) than the center of room ambient temperature, so how anyone can claim it controls room temperature, it controls the heat output from the radiators. A TRV simply cannot work out what the center of room temperature is or when to turn it on or off, since it is overshadowed by immediate stronger heat from the rads, hence our friend (OP) is right that TRVs main sensing is not sensing variations in room temperature but it senses heat from the radiator, which in turn heats the immediate air around it and can also get influenced to a degree by the actual flow of hot water through its body as some heat can effect it directly by hot water flowing through its body, despite being thermally isolated from the main body.
Since it sits pretty close to a radiator, it therefore senses immediate emission of heat radiating from it, if you take your digital thermometer, you will see that all areas around the radiator are far hotter than any other distance areas, like the middle of the room, and since TRV sits right close to a rad, it, so it can therefore be said that a TRV controls the room temperature indirectly by controlling the amount of heat going into a radiator, which in turn radiates limited amount of heat.
Hence a TRV is not an accurate and most appropriate method for controlling a room temperature to a very close level, and will not respond to drafts and sudden cooling so has a long response time. But for cost and practicality, it does a fairly good job. i.e. it limits excessive heating of the room, by controlling the amount of heat input to rads, this is how one can save on energy bills.
You most likely know that many people turn some rads off or have them turned just 1/4 turn on so as to keep very mild heat in an unused room, this is because the heat radiated from limited flow of CH flow water that could be at 90c but overall rad temperature stays luke warm, due to restricted flow and so heat escape (radiation ) is greater than heat input, so basically a TRV only controls the radiator output heat output and not the room temperature, conversely the room heats to a certain temperature depending on the heat emitted by a radiator, and that depends on the amount of heat flowing into it, controlled by the setting of TRV.
If I may parallel it to an electrical fan heater without a thermostat control, with two settings, 1kw and 2kw, one can choose which setting to use and higher setting will heat room a lot more than a lower setting, since you are controlling heat output and not room temperature.
I will try and refine all of above in one line:
A TRV controls heat output from radiators and is not a prime room temperature control device.
As it stands the definition of TRV - Temperature controlled Radiator Valve, whose prime function is to control radiator temperature, which in turn controls room temperature.
This is what OP said in the beginning in his first post: (though little bit misconstrued as it is not the radiator water temperature but immediate heat emitted from the radiator, which of course depends on the water temperature, if the rad was made of heat insulating material it would not radiate heat despite you may be flowing through it boiling hot water) but ya pretty close.
Your average TRV works by sensing the radiator water temperature (it's bolted to it, after all) and I need something that actually senses the room temperature, to respond to opening the door and whether or not the woodburner is alight. I don't want to go to the bother of Zones.
Read more: http://www.diynot.com/diy/threads/improving-on-trv.454988/#ixzz42e0rMVUl
Oh I may add, this is the reason why only silly people would put a room thermostat above a radiator. A room thermostat is never fixed too close to a radiator as it would not give an accurate temperature setting, or one will have to set it to a lot higher temperature to get the space warm, too close and low setting it will trip in and out whilst the room may not have reached the desired temeparture, and the same goes for those who install it much further away!
Since it sits pretty close to a radiator, it therefore senses immediate emission of heat radiating from it, if you take your digital thermometer, you will see that all areas around the radiator are far hotter than any other distance areas, like the middle of the room, and since TRV sits right close to a rad, it, so it can therefore be said that a TRV controls the room temperature indirectly by controlling the amount of heat going into a radiator, which in turn radiates limited amount of heat.
Hence a TRV is not an accurate and most appropriate method for controlling a room temperature to a very close level, and will not respond to drafts and sudden cooling so has a long response time. But for cost and practicality, it does a fairly good job. i.e. it limits excessive heating of the room, by controlling the amount of heat input to rads, this is how one can save on energy bills.
You most likely know that many people turn some rads off or have them turned just 1/4 turn on so as to keep very mild heat in an unused room, this is because the heat radiated from limited flow of CH flow water that could be at 90c but overall rad temperature stays luke warm, due to restricted flow and so heat escape (radiation ) is greater than heat input, so basically a TRV only controls the radiator output heat output and not the room temperature, conversely the room heats to a certain temperature depending on the heat emitted by a radiator, and that depends on the amount of heat flowing into it, controlled by the setting of TRV.
If I may parallel it to an electrical fan heater without a thermostat control, with two settings, 1kw and 2kw, one can choose which setting to use and higher setting will heat room a lot more than a lower setting, since you are controlling heat output and not room temperature.
I will try and refine all of above in one line:
A TRV controls heat output from radiators and is not a prime room temperature control device.
As it stands the definition of TRV - Temperature controlled Radiator Valve, whose prime function is to control radiator temperature, which in turn controls room temperature.
This is what OP said in the beginning in his first post: (though little bit misconstrued as it is not the radiator water temperature but immediate heat emitted from the radiator, which of course depends on the water temperature, if the rad was made of heat insulating material it would not radiate heat despite you may be flowing through it boiling hot water) but ya pretty close.
Your average TRV works by sensing the radiator water temperature (it's bolted to it, after all) and I need something that actually senses the room temperature, to respond to opening the door and whether or not the woodburner is alight. I don't want to go to the bother of Zones.
Read more: http://www.diynot.com/diy/threads/improving-on-trv.454988/#ixzz42e0rMVUl
Oh I may add, this is the reason why only silly people would put a room thermostat above a radiator. A room thermostat is never fixed too close to a radiator as it would not give an accurate temperature setting, or one will have to set it to a lot higher temperature to get the space warm, too close and low setting it will trip in and out whilst the room may not have reached the desired temeparture, and the same goes for those who install it much further away!
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More clueless drivel from the child hater.
Radiators radiate very little for a start.
Radiators are also a pish poor way to heat a room.
Now try and conjugate those two concepts....
Radiators radiate very little for a start.
Radiators are also a pish poor way to heat a room.
Now try and conjugate those two concepts....
that's what got me in the beginning, OP wants an extremely accurate high tech way of regulating the temperature whilst heating a room with the most archaic method of all.
Gotta start at the beginning if you want to do it right.
Gotta start at the beginning if you want to do it right.
I want a 'better' way to do the job with the system I already have. I've already found that wireless control is flexible and that's why I like the idea of wireless control and 'proper' valves, which give good proportional control. I imagine that those two links I gave went down really well and you all read them from beginning to end - haha. They were written by people with more basic knowledge than has been demonstrated here and they are due some respect.
From the responses I have gathered here, it would be unlikely if any members of this forum would recommend anything else but "the most archaic method of all" for a replacement. If electrical energy were a reasonable price, electrical heating would be the best way to go because it is easy to instal, to modify and to control.
"Gotta start at the beginning if you want to do it right" absolutely right. I did just that, thirty years ago (with available tech and a friendly local guy) and it was very successful, as far as it went. The three other houses we have owned were not very good and I am trying to get this one better. I am staggered why this seems to have caused such an upset here.
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