Improving on TRV

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This thread is full of useful snippets and there is clearly a lot of specialist knowledge about CH systems. I am grateful for what I have learned. But we could have got to this point a lot quicker if people had read my earlier posts with a bit of empathy and sussed out what I really needed to know. Just because a problem is posed in slightly alien terms doesn't mean that the questioner is dumb or ill informed. If the cost of getting information from this forum is that you mustn't upset the regulars by using strange or slightly academic terms then this wealth of knowledge is not accessible and the forum is wasted.
From the way the information is tightly metered out, you would question the motives of some of the 'experts' in posting at all. Ploughing through all the dismissive and offensive 'banter' is hard work and many people would have been put off long before the end of the six pages of posts on this thread.
I don't know why members react to a searching query as if it were a personal attack. If I have used terms that are too technical and unfamiliar then why should it be assumed to be BS? Fact is that the ones who shout loudest, know least.
Someone mentioned Wikipedia. Perhaps some of you should try that as a way into understanding how control systems work. Wiki is not 100% always but in basic topics like this, it is pretty reliable. It is ignorant to dismiss Wiki when you don't understand what it is saying. Every radiator you have ever installed is following the laws of Physics, remember.
It would be a shame if someone reading this thread came to the conclusion that the CH engineering community was a little isolated group who resist change on principle and can only respond to it with insults and nasty language. If the more moderate (and helpful) regular contributors were brave enough to point this out to the more childish ones, the forum could be a much more useful and friendly place. I can't imagine the childish ones would be reading to the end of a post as long as this one. They are more likely to have left and gone out in the street for a fight with the other kids out there.
 
Soapy, well done for pioneering the development of central heating controls. It is a sorely neglected field with no one doing R&D due to lack of commercial interest.
 
OP. You opened this thread on a totally incorrect assumption and when told you were wrong went on demanding proof because you didn't believe people who do this for a living. All the proof you needed is in the product literature.

As for my reference to Wikipedia, that was because of your terrible writing style. Typical of someone with your attitude.

If has nothing to do with having empathy or not.
 
sophiecentaur said:
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.
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Which is a logical assumption for someone who has not been trained in central heating equipment.

An explanation about the thermal barrier between water pipe and "sensor" ( the container of wax ) would have been al that was needed. Adding some links to sites where the operation of a TRV was explained would be worth including. Some of those sites would include details of how the operating points of various type of TRV are affected by the temperature of the water passing through them. ( heat from the pipe work does affect the operating points of the TRV relative to room air temperature )
 
It's the time the valve takes to go from one extreme to the other.

Seeing as it's proportional control this figure is fairly meaningless in the context of comfort unless you have a room that can get from 14 degrees to 28 degrees in under 20 minutes.
 
A well made boiler such as Vaillant VCW221 GB installed in 1994 April, so now coming to nearly 22 years in service, still running good, on its original pump, which is the only part more likely likely to suffer abnormal wear & tear running continuously.

I have been running my heating in this mode for many years with no break down (touch wood) so far.

Electric heating is only ever used to top up extra heat in the bedroom and bathroom just a few degrees more taking a shower, or before and after going into bed, so normally no more than about 15minutes and at no more than 2kw.

My gas bills are the same as my neighbours and yet their house feels colder as they tend to put heating on timed. My bill may be £20-£40 more per quarter, thats about it, I know since all my neighbours moan at how big a gas bill has landed!
 
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The definition of response time is whatever anyone chooses to define it as.

As a practical engineer my definition would be the time taken to change from 10% to 90% of the flow rate with a temperature difference of say 2 degrees!

But as Dan says, the intention is that they are used as a fully variable flow rate device so the response time is practically only required to be compatible with the response time of the radiator that it is controlling.

The reality is that there are too many variables involved and the objective of TRVs is to provide adequate temperature control at an acceptable cost.

In my view while wax TRVs do provide some control the response time is pretty slow and therefore not ideal. I therefore like to provide TRV4s for my clients.

Tony
 
Dan Robinson said:
It's the time the valve takes to go from one extreme to the other.

Seeing as it's proportional control this figure is fairly meaningless in the context of comfort unless you have a room that can get from 14 degrees to 28 degrees in under 20 minutes.
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That is a meaningless definition - if it's correct. I have learnt that it is defined in BS EN215-1 but, as usual, the text of this Standard is not available on the internet.
 
Why is it meaningless?

OT tells you exactly what the term is referring to. There is only so much rate of change the liquid /wax can do.

I suspect also, the rating is fairly loose too as, as previously stated, there are many variables. The neurosis of the occupant being one of them.
 
In digital electronics response time is quoted as propagation delay, that is time it takes for an output (reaction) to change from when an input was initiated.(action)
and yes it is usually timed from when it changes by 10% and measurement stops at 90% change.
 
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I have already quoted that 10% to 90% which is often used for many engineering purposes!

Most electronic controls intentionally include a set delay before the planned change takes place.

Traffic lights being one example we see every day!

Tony
 
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