Improving on TRV

[sophiecentaur]

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.
What I think I need is a valve with a remote (could be wired) room temperature sensor. The electronic TRVs appear to work on the local water temperature - or am I wrong?
Also, many of the existing Drayton TRVs are falling apart. The plastic fingers under the metal securing ring have just disintegrated. Can I get replacement control heads that are more robust but compatible?
Cheers in advance.

 

[Aquaheat]

You are wrong.

TRVs measure room temperature and operate the radiator on or off within about +/- 1.5C of the set temperature.

You can get TRVs with remote heads.

Would need a picture of the valves or a model name to know whether they are still available or a compatible one will fit.

Jon

 

[sophiecentaur]

Thanks for replying.
It would be nice if I could believe that but how can it be guaranteed, with the radiator right next to it and the hot water valve right underneath it? It must assume that the air circulation through the sensor is enough to make the room temperature dominate.
With respect, is there written evidence of the sort of performance you quote or is it just advertiser's figures? I have only ever dealt with the crude 1.2.3.4.5.Max style TRVs.
In any case, +- 1.5C is quite a wide range when it comes to the subjective effect around 21C and I really would like to be able to rely on something a bit better, that senses the room temperature from some distance away.
The present TRVs are Drayton TRV 4 models. Here's hoping there's a compatible alternative.

 

[endecotp]

Get yourself a thermometer with a small probe (e.g. a kitchen food temp thermometer) and poke it through the holes in the top of your TRV. Does it read closer to the room temp or the water temp?

 

[hazetimesfive]

Thanks for replying.
It would be nice if I could believe that but how can it be guaranteed, with the radiator right next to it and the hot water valve right underneath it? It must assume that the air circulation through the sensor is enough to make the room temperature dominate.
With respect, is there written evidence of the sort of performance you quote or is it just advertiser's figures? I have only ever dealt with the crude 1.2.3.4.5.Max style TRVs.
In any case, +- 1.5C is quite a wide range when it comes to the subjective effect around 21C and I really would like to be able to rely on something a bit better, that senses the room temperature from some distance away.
The present TRVs are Drayton TRV 4 models. Here's hoping there's a compatible alternative.

It's guaranteed.

The mechanism is designed to take into consideration the proximity of the pipework.

 

[45yearsagasman]

It would be nice if I could believe that but how can it be guaranteed

Just believe what the experts have said. TRV's have been around longer than you probably have, and are a proven way of controlling a room temperature.
It may be that your existing valves are ready for a complete renewal. You may be able to get replacement heads for yours, but I think in this case a complete valve will sort you out..........in a manner of speaking.

 

[BigSnoopy01]

common misunderstanding is that a trv controls the radiators temp not the rooms. a remote head trv will move the sensor away from the radiator.

 

[Dan Robinson]

Thanks for replying.
It would be nice if I could believe that but how can it be guaranteed, with the radiator right next to it and the hot water valve right underneath it? It must assume that the air circulation through the sensor is enough to make the room temperature dominate.
With respect, is there written evidence of the sort of performance you quote or is it just advertiser's figures? I have only ever dealt with the crude 1.2.3.4.5.Max style TRVs.
In any case, +- 1.5C is quite a wide range when it comes to the subjective effect around 21C and I really would like to be able to rely on something a bit better, that senses the room temperature from some distance away.
The present TRVs are Drayton TRV 4 models. Here's hoping there's a compatible alternative.

Are you serious?

 

[Phill Peck]

Thanks for replying.
It would be nice if I could believe that but how can it be guaranteed, with the radiator right next to it and the hot water valve right underneath it? It must assume that the air circulation through the sensor is enough to make the room temperature dominate.
With respect, is there written evidence of the sort of performance you quote or is it just advertiser's figures? I have only ever dealt with the crude 1.2.3.4.5.Max style TRVs.
In any case, +- 1.5C is quite a wide range when it comes to the subjective effect around 21C and I really would like to be able to rely on something a bit better, that senses the room temperature from some distance away.
The present TRVs are Drayton TRV 4 models. Here's hoping there's a compatible alternative.

Are you serious?

I not gonna recommend evo home with remote sensors? Do I suspect the budget might not meet the requirements.

 

[Dan Robinson]

You gotta love an argument from ignorance

 

[sophiecentaur]

You gotta love an argument from ignorance

If someone could actually quote some performance figures then I would no longer be "ignorant". This is what bothers me; I have looked for a table or graph, showing the room temperature achieved in various situations with the same TRV setting and I can't find one.
I am can't accept what's written here as 'fact' without some evidence. Opinions are valuable and advice, based on experience of using equipment is also useful.
But I wouldn't dream of buying a TV, Camera, HiFi, Car or savings account without some proper performance figures and I am reluctant to go for a heating system on a verbal basis. Is that unreasonable?

 

[hazetimesfive]

performance figures? what are you talking about?

There is a very strong reason why you cannot find what you are looking for.

TRVs turn the radiator on and off depending on the setting and the current air temp, that's all they do

 

[sophiecentaur]

[/QUOTE]
I not gonna recommend evo home with remote sensors? Do I suspect the budget might not meet the requirements.[/QUOTE]
I am prepared to spend what's necessary to get the result I want. I would be interested to know what's wrong with evo home. Is it reliability of valves?
I understand control theory and the notion of a remote sensor makes serious sense. The only problems should be reliability and temperature measuring accuracy. In a TRV, the air circulating so close to the sensor is the equivalent to an extra feedback path in the loop. The basics apply in any control system.

 

[hazetimesfive]

What is the result you want? I've met very few who are unhappy with a traditional heating system, most simply don't care about the degrees, they just want to feel warm and not be too hot.

Remote sensor TRVs are only used when the radiator is boxed in. Standard TRV systems work fine, why is it that you think they do not?

 

[sophiecentaur]

performance figures? what are you talking about?

I should have thought that any 'expert' in the field would know. A car designer - or even just a well informed hobbyist would know the relevant figures on their car performance so why not a CH engineer?
Central Heating Design is a branch of Engineering. In serious Engineering, a system is designed, built and then tested to assess how well it functions. Why should CH be any different? Heating is big business and efficiency is a hot topic these days. The actual numbers count. Where are they?
The sort of figures that it would be reasonable to expect would be typical room temperature variations under different conditions - doors open, cooker running, alternative heaters running. Not hard to obtain and could be available if a manufacturer is confident enough to publish examples.
Selection based on personal experience and recommendation alone doesn't instil the confidence that hard figures can provide.

TRVs turn the radiator on and off depending on the setting and the current air temp, that's all they do

The control is proportional, and not just on/off .