Could heating systems be improved with this idea?

[vexation]

85

why doesn't you last remaining rad,in the hall, sink the heat away? Have you got a TRV on that too? Set colder than the room stat?

This hall rad is the one without the TRV and is the one that you suggested turning down. I might have got a bit carried away turning it down (it had just wilted a fig plant on the upper level) - so the remaining path was pretty resticted.

85 was how it was left after install. I see 82 is more the norm.

 

[JohnD]

it would seem to be necessary to identify the last room to reach it's desired comfort temperature before the stat is fitted in that room.

You can define that room, rather than identifying it.

You do this by adjusting the lockshield so that the rate of heat of that room is lower than all the other rooms, so that it will be the last to get hot and the first to get cold. best if it is a living room that will "always" be occupied so there is no reason to change the rad settings.

IMO the hall is not the best place to put the wall stat; as you say if it is tall the heat will all rush upstairs.

In my newly upgraded system, the boiler monitors heat loss (compares water temp on return to water temp on flow, I think) and modulates its power output down as they get closer; and the pump modulates itself to reduce flow as the rads gradually shut down on their TRVs.

I am just a householder and I don't know the usual temp setting for other boilers, my new one has the "normal" setting (per manufacturer's advice) at 60C but they say you can turn it up if in excptionally cold weathetr the house is not warm enough. I have mine at 70C at the moment to heat the HW cyl faster, at full output it is more than enough for my house.

 

[vexation]

it would seem to be necessary to identify the last room to reach it's desired comfort temperature before the stat is fitted in that room.

You can define that room, rather than identifying it.

You do this by adjusting the lockshield so that the rate of heat of that room is lower than all the other rooms, so that it will be the last to get hot and the first to get cold. best if it is a living room that will "always" be occupied so there is no reason to change the rad settings.

Good point, but I'd prefer my most used room to warm up the quickest!

IMO the hall is not the best place to put the wall stat; as you say if it is tall the heat will all rush upstairs.

And commit figicide on the way

In my newly upgraded system, the boiler monitors heat loss (compares water temp on return to water temp on flow, I think) and modulates its power output down as they get closer; and the pump modulates itself to reduce flow as the rads gradually shut down on their TRVs.

Is it a condensing boiler? Mine is a modulating condenser but it doesn't have that kind of fancy pump control. I like the sound of yours!

I am just a householder and I don't know the usual temp setting for other boilers, my new one has the "normal" setting (per manufacturer's advice) at 60C but they say you can turn it up if in excptionally cold weathetr the house is not warm enough. I have mine at 70C at the moment to heat the HW cyl faster, at full output it is more than enough for my house.

Wow, thanks. That's something I'll be looking in to now.

 

[Paul Barker]

I think you'd agree though that a satisfied room stat does not necessarily indicate that all rooms are satisfied. In an attempt to ensure this, it would seem to be necessary to identify the last room to reach it's desired comfort temperature before the stat is fitted in that room.

I would prefer to see a democracy where the vote of every TRV counts equally rather than be subject to the tyranny of a single dictator

Sir you are brilliant in your fresh approach to a badly imposed issue by government.

most houses would have been better served by an intelligent heating engineer left free to design without constraints.

My own house has no trv's correctly sized and balanced radiators and a single stst in the hall. There is no room too warm there is a plesent even cool temperature to the whole house which we adjust with our clothing. When we go outside into the cold we don't feel cold as we have learned to harness our body heat.

TRV's are useless and an excuse for not designing the system whatsoever. just pop the rads wherever they fit regardles of calculations join them up with plastic bang a b and q boiler on the wall fire it up collect the money and run.

What you have highlighted is a massive floor in the imposed method, Each room should get a vote. surely in todays world where you can buy rf equipment from china for £2.50 each room could have a vote with a radio stat each room's receiver at the boiler would interface through a relay so the last room has to be satisfied before the boiler is cut. The only problem is how to shut off the hydraulics to each room as it is satisfied. Sadly (on cost grounds) it would have to be a zone valve per room.

Or just go back to what I have correctly sized balanced rads keep your house below warm and adjust your personal body temperature with appropriate clothing.

 

[fitz1]

you sound like a grumpy old man, paul.If the kids complain about being cold you tell em to put a jumper on.saving the planet eh. lol

 

[simond]

What you propose and more besides has been available for 7 years and is called Honeywell Hometronic.

A remote control room by room temperature monitoring TRV interlocked with the boiler, using RF comms. We fit a few a month and the customer feedback, in terms of comfort and energy saving, is all good. In fact I have a system here at home. I carry a whole install kit in my van to demonstrate it, because you have to see it to appreciate how clever it is (if you are not a heating engineer).

If you want to save further energy fit a boiler that does not need pump overrun, such as the domestic Buderus (sadly recently elbowed out of the UK market by Worcester Bosch's marketing dept) or a Kidd boiler.

 

[Paul Barker]

you sound like a grumpy old man, paul.If the kids complain about being cold you tell em to put a jumper on.saving the planet eh. lol

Funnily enough they don't complain because they have always lived in a cold drafty huge roomed house where the prvailing wind comes from Iceland.

It is perfectly easy to acclimatise your body, once done you are as comfortable as the idot with heating blasting away.

my son can't sleap in his friend's houses because they are so hot. usually the single mums who have the heating so high.

And you're right i woke up this morning with my grumpy old man head on. It's kind of good therapy to vent it here once in a while.

Well the world is so full of bafoons leading their insignificant lives so poorly someone has to say something.

 

[vexation]

Paul, I'm actually quite impressed with the functioning of the TRVs in my home. Just to repeat, the only thing that I feel lets it down is the decision about boiler demand.

What you propose and more besides has been available for 7 years and is called Honeywell Hometronic.

A remote control room by room temperature monitoring TRV interlocked with the boiler, using RF comms.

Right, but far too expensive for most I suspect. And how is each rad. valve and RF thermometer powered in every room? From what I can see the conventional TRV is all that's needed to transduce the signal for boiler demand. The pressure/flow rate in the system must reflect this and can be sensed at a single location. This could be done at a fraction of the cost of the Hometronic and even be a simple retrofit.

If you want to save further energy fit a boiler that does not need pump overrun, such as the domestic Buderus (sadly recently elbowed out of the UK market by Worcester Bosch's marketing dept) or a Kidd boiler.

That sounds interesting. Pump over run, I assume, is a fixed time period after the burner shuts off in which the pump is kept running to dissipate heat from the heat exchanger -- when demand is off? If so, the saving would only seem to be in the electricity used by the pump running for 5 minutes or so?

 

[BigBurner]

if all rads have trvs and an auto bypass is fitted , why cant we discard the roomstat.

Because you need a control interlock. This means that when no heat is called in the house the burner is off.

 

[BigBurner]

Paul, I'm actually quite impressed with the functioning of the TRVs in my home. Just to repeat, the only thing that I feel lets it down is the decision about boiler demand.

TRVs on all rads. That is got around by:

1. Fitting a Willo Smart pump - auto variable speed - external to the boiler and disconnect the pump in the boiler, if one is in there. Some makers may approve of a straight swap to a Smart pump if the pump is in the boiler casing. The time clock switches the Smart pump on and it is always on when the CH clock calls for CH
2. Fit a flow switch after the Smart pump
3. Wire the root stat circuit through the flow switch.
4. Do not use a room stat

When all TRVs are closed the Smart pump is off. When they open gradually it winds up.

If no flow as all TRVs are closed the flow switch switches out the burner.

A modulating boiler will wind down the burner as the TRVs close up.

 

[namsag]

If the original question was why cant we have trvs on every rad without a room stat and the boiler shuts of when all the trvs close then .
Then yes this has already been designed and is called a flow switch several boilers incorporate them and it is perfectly acceptable under partL and is another way of creating an interlock

 

[BigBurner]

If the original question was why cant we have trvs on every rad without a room stat and the boiler shuts of when all the trvs close then .
Then yes this has already been designed and is called a flow switch several boilers incorporate them and it is perfectly acceptable under partL and is another way of creating an interlock

Some of the Bax/Potterton range have integral flow switches. What others do?

 

[namsag]

Should find some articles in trade publications .

 

[simond]

Vexation wrote:

That sounds interesting. Pump over run, I assume, is a fixed time period after the burner shuts off in which the pump is kept running to dissipate heat from the heat exchanger -- when demand is off? If so, the saving would only seem to be in the electricity used by the pump running for 5 minutes or so?

Simond writes

How can the only saving be the pump electricity? If you are going to design heating controls you have a long way to go......

Where do you think the heat from the heat exchanger goes on pump overrun, and where is the demand for it?

Yes, that's right, it is wasted. Of course I'm not worried about the energy used by the pump, that is insignificant by comparison.

[/quote]

 

[vexation]

Vexation wrote:

That sounds interesting. Pump over run, I assume, is a fixed time period after the burner shuts off in which the pump is kept running to dissipate heat from the heat exchanger -- when demand is off? If so, the saving would only seem to be in the electricity used by the pump running for 5 minutes or so?

Simond writes

How can the only saving be the pump electricity? If you are going to design heating controls you have a long way to go......

Where do you think the heat from the heat exchanger goes on pump overrun, and where is the demand for it?

Thanks for making all my question marks worthwhile. My intention on starting this topic was to learn stuff in a new area of control. My motive is to see if I can improve on the comfort and economy of my own home. I don't think this is out of the question despite my meager capabilities.

Thanks BigBurner, I like the sound of that "Willo Smart pump" But is this it...?
http://www.screwfix.com/prods/33590...mps/Wilo-Smart-Pump-Domestic-Circulating-Pump

You've described the kind of plan I had in mind, although I'm a bit concerned about how the boiler will cope the instant the pump stops circulating? OK, the flow switch cuts the burner at the same time, but there was a reason for having pump overrun and that seems to have been eliminated.