Radiator Thermostatic Valves and Central Heating Programmer/Wireless Thermostat - Help please

ArthurN

Hi,
Like a lot of people, I'm being confronted with my previous lazy ways with household energy, and realising that it isn't affordable anymore.
I have a modernish reasonably efficient house, a Worcester sealed gas central heating boiler and thermostatic radiator valves fitted all over the house. Hence my first question really. The only room in the house apart from bathrooms that doesn't have a thermostatic valve is the kitchen. I'm getting the impression that whoever fitted the thermostatic valves for me should have known better.
Anyway, I am where I am. Should I attempt to put the programmable wireless thermostat/controller in that said kitchen as a first step?
We have had it in the lounge mainly, for years, but the two radiators in there are fitted with thermostatic valves. So this is wrong?
I will freely admit, I know I haven't the foggiest on how to use thermostatic valves so they all get left on 5 or MAX anyway. Which is pointless, I know.
Then where do I start? Turn the heating on max for an hour, and see which rooms are too hot? Seems wasteful. When I turn a thermostatic valve down, what actually is happening? As I understand it, I'm not turning the temperature down, so what am I doing? Why bother turning them down then?
Sorry to be a numpty, but I could really do with getting my head round this, and starting off from a sound base of knowledge.
If anyone can spare the time to assist me, I would be very grateful, and hopefully the thread will help others.
N.

jennifernil

The valves regulate the heat in each room, so you need to find the setting that you are comfortable with for each room.

On our, very old, system we have TRVs on all rads other than the hall, which only has a small rad anyway.   Lounge needs about 3.5 setting, bedrooms 1 at the most, more often off, bathrooms 3.5.

The basic idea these days is that the thermostat is in your most used room.....the lounge probably, and that rad should have no valves.

I won't say any more on that as it is not how we run our system, other than that I feel there is a conflict between the demand for heat in the other rooms and the workings of the thermostat.   We control our system via a timer and the valves.

ArthurN

It looks like a bit of experimentation is in order!

Unfortunately, the room we most often use is the lounge, which got fitted with TRVs, meaning that I'm not sure it's the best room to put the controller with the inbuilt thermostat, into. 

Still, all thoughts are potentially useful, and I glean little bits from most of them, so thank you very much for responding, appreciate it! :-)

N

Bendy_House

Ha-ha! Yes, it's a conundrum!

Ok, first things first. TRVs on the rads respond only to the room's temperature, and will open and close the valve depending ONLY on this. '2' roughly represents ~17-ish degrees, I think, and '3' more like 20oC. '1' will be, I dunno, 12-ish? You get the idea, and this can be looked up easily. So, when you turn up a TRV, the valve will open IF the room's temp is less than the valve setting. If your room is at 15oC, the valve will open as you turn it up past, ooh, 1-2 and upwards. Of course, the actual rad won't come ON unless the boiler is also running; the TRV has no direct communication with the boiler.

So, TRV settings. Any room which does not require heating for any significant time should have its TRV turned down to around ~1. These rads will then only come on if the temps in these rooms get very low - <10oC-is - and that is absolutely fine for an unused room. Any truly unused rooms - bedrooms where the kids are away at Uni (sob...) - should have their TRVs set at '1', and have their windows cracked open at vent setting. Close the door, forget about them, break down sobbing.

The ROOM stat is what controls the actual boiler. Yours is programmable, which is a good thing; this should be set to provide 'comfort' when it's needed, and 'background' at other times. Your call, but I, for example, have mine set to 14oC for overnights (10pm- to 6am), and it only ever comes on if it's very cold outside. I then have it set at 18oC for daytime use when folk are out and only I'm at home. I have found, for our house, that 18oC is fine - again, it very rarely comes on during the day (due, I guess, mainly to solar gain), and having the house at 18oC means it comes back up to comfort levels pretty quickly when needed - ie when folk come home. Then, it's 20oC at 6am for an hour or so, and 20oC from 5pm onwards. This works for me, and you'll soon find out what works for you. I have just fitted a cheap WiFi Prog Stat to allow phone App control, because when we're sitting watching the old series of Dexter, with a blanket over our knees, it's easy to knock a degree off the 'stat to save energy.

Ok, so where does the Prog Stat go?! The answer, I'd suggest, is either in a room or part of the house which should be kept at a constant temp and is generally unaffected by other heats sources (which is why it was traditionally the hallway), or else in the 'main' living area where you do want the most even and controllable temp - all other rooms are secondary... So, that is the sitting room. And the room with the Prog Stat should NOT have TRVs on the rads, or the two systems will 'fight' eachother. That does not mean that you need to remove the TRVS, since turning them (the sitting room ones) up to '5' or 'max' means they are effectively always open, which is what you want. You can even unscrew their heads if you prefer - then they are truly fully open.

A big reason why the kitchen is not a good location for the PS is that cooking will very likely increase the temp in there, and that would then turn the 'stat off before the rest of the house is warm. By the SAME token, if you have a secondary source of heating in the sitting room - a log burner or similar - then the sitting room is also not the best place for the PS; when you think about it, your sitting room will heat up quickly, you'll be warm and toasty, but the boiler will shut off and the rest of the house will go cold. So, if you have secondary sources of heating in the SR, then move the PS to the hallway - AND fit TRVs set to '3' in the SR, so the SR rads go off when not needed, but the rest of the house can carry on.

Phew. So, the room with the PS should NOT also have TRVs (or remove their heads/set to 'max').

That's the principle. Now comes the practicalities...  Your radiators should ideally be 'balanced' so that they heat up at roughly the same rate to suit each room. So, a smaller rad in a bedroom should heat that room at the same rate as a couple of larger rads will heat the larger (and warmer) sitting room. That way, when the boiler is on, it should allow all the rooms in the whole house a fair chance to get to its intended temps all at the same time. Once you've repositioned the PS to the 'best' location (if it's already in the SR, that's fine - provided you don't also have a secondary heat source, in which case chuck it in the hallway), then (a) make sure the TRVs in the PS room are fully 'open', and see how it goes. Set the PS to give the temps you want in THAT room, so that would likely be 20oC for the sitting room, but likely only 18oC for the hallway? Now monitor how well this works for the whole house over the next few days.

If you find that your sitting room gets warm and toasty very quickly and then turns off the boiler BEFORE the bedrooms/bathroom/kitchen/hallway etc have warmed up fully, then it's clear the SR's rads are set to be too 'powerful'. They then need 'balancing' - tweaking down to reduce their output - using the 'lockshield' valve which is on the OPPOSITE side to the TRV (which should always be at MAX 'cos the PS is also in that room). This should slow down how fast the SR rad heats up, and it'll then take longer for the PS to turn off - this gives the rest of the house time to also get to temp. (Oh, I should have added - when you COMPARE how fast rooms heat up, then ALL the rooms should have their TRVs set to 'max' so that you are actually comparing radiator outputs, and not the variable effect of the TRV control.)

If you think the hallway is the more stable and consistent of heating environments, then move the PS there instead, and open its TRVs to 'max'/or remove head. Then see how things go. If the hallway gets too hot, too quickly, so shuts off the PS before the SR and the rest of the house is warm, then tweak down the LS on the hallway rad to slow it down.

Well, you did ask...

Whatever you do, turn these bludy TRVs down to the actual temps you need for each room! Unused rooms = '1', and vent them :-)

ArthurN

Bendy_House said:

Ok, so where does the Prog Stat go?! The answer, I'd suggest, is either in a room or part of the house which should be kept at a constant temp and is generally unaffected by other heats sources (which is why it was traditionally the hallway), or else in the 'main' living area where you do want the most even and controllable temp - all other rooms are secondary... So, that is the sitting room. And the room with the Prog Stat should NOT have TRVs on the rads, or the two systems will 'fight' eachother. That does not mean that you need to remove the TRVS, since turning them (the sitting room ones) up to '5' or 'max' means they are effectively always open, which is what you want. You can even unscrew their heads if you prefer - then they are truly fully open.

Well, you did ask...

Whatever you do, turn these bludy TRVs down to the actual temps you need for each room! Unused rooms = '1', and vent them :-)

Wow!

In all my years of posting the odd request for help on a forum, I don't think I have ever received such a well-considered, knowledgeable, funny, poignant, completely relatable (the Dexter comment was spot on!) response.

It's completely heart-warming, a really big thank you to you, for taking the time to write that. I'm sure it is going to help plenty of people, it really is.

I had heard that the problem with TRVs and a PS in the same room could lead to a dispute between them. I did not though, know that you could negate that by turning up the TRVs to the maximum, so that is very useful info.

You were also spot on in that we have a woodburner in the lounge, and cold bedrooms after a session of a having a lovely evening with it on!

Knowing best how to deal with that, without wasting stupid amounts of energy, has become a life ambition! Again, I believe I now have ammunition to tackle these problems :-)

Thanks once again, am moving the PS to the hall as we speak, and will try that.

Bendy_House

Damn, I could have just said, "move your bludy PS to the hall..." :-(


(Thank you )

FreeBear

ArthurN said: we have a woodburner in the lounge, and cold bedrooms after a session of a having a lovely evening with it on!

Have a (multifuel) stove in my lounge - It is a bit oversized for the size of the room, so can get mighty toasty in there... The bedroom above gets a little warmth from the flue running up inside the chimney, and I also leave internal doors open. Once all the draughts are plugged and I've finished insulating the walls, I may not need to use the gas boiler.

ArthurN

FreeBear said:

ArthurN said: we have a woodburner in the lounge, and cold bedrooms after a session of a having a lovely evening with it on!

Have a (multifuel) stove in my lounge - It is a bit oversized for the size of the room, so can get mighty toasty in there... The bedroom above gets a little warmth from the flue running up inside the chimney, and I also leave internal doors open. Once all the draughts are plugged and I've finished insulating the walls, I may not need to use the gas boiler.

I had noticed with some friends that there was a tendency to chuck in a wood burner that filled the hole, and that consequently, when running efficiently, you practically had to open the windows to breathe! LOL!

We got a smaller one that can burn all evening, generate a certain amount of heat upstairs as well, given time, and we've been happy with that.

Now, with energy prices the way they are, being comfortable, without being broke, is what we are trying to achieve now.
That means, learning about the equipment we use, rather than wasting energy.

Our flue goes outside, so no help there!

twopenny

Following carefully as I had a similar question.
But after reading ultimate guide above I'm doing something right though have my own clueless bit so I'll post a 'part 2' thread when my head's cleared.
Thank you Bendyhouse and others. 

BUFF

ArthurN said:

Hi,
Like a lot of people, I'm being confronted with my previous lazy ways with household energy, and realising that it isn't affordable anymore.
I have a modernish reasonably efficient house, a Worcester sealed gas central heating boiler and thermostatic radiator valves fitted all over the house. Hence my first question really. The only room in the house apart from bathrooms that doesn't have a thermostatic valve is the kitchen. I'm getting the impression that whoever fitted the thermostatic valves for me should have known better.
Anyway, I am where I am. Should I attempt to put the programmable wireless thermostat/controller in that said kitchen as a first step?
We have had it in the lounge mainly, for years, but the two radiators in there are fitted with thermostatic valves. So this is wrong?
I will freely admit, I know I haven't the foggiest on how to use thermostatic valves so they all get left on 5 or MAX anyway. Which is pointless, I know.
Then where do I start? Turn the heating on max for an hour, and see which rooms are too hot? Seems wasteful. When I turn a thermostatic valve down, what actually is happening? As I understand it, I'm not turning the temperature down, so what am I doing? Why bother turning them down then?
Sorry to be a numpty, but I could really do with getting my head round this, and starting off from a sound base of knowledge.
If anyone can spare the time to assist me, I would be very grateful, and hopefully the thread will help others.
N.

For the TLDR version of B_H's magnum opus:

The programmer/roomstat controls when your boiler actually fires (according to time & temperature set) & pumps hot water around the heating system.

The TRVs (where fitted) control whether hot water is allowed to flow through individual radiators according to local temperature. TRVs do not control the speed at which temperature rise (so opening them up higher does not speed up the rate at which a room reaches set temperature.) but the max temperature at which they close.  As a rough general guide (but you should check for exactly what you have fitted)  markings correspond to:

0 = Off.
* = 7°C.
1 = 10°C.
2 = 15°C.
3 = 20°C.
4 = 25°C.
5 = 30°C.

In general, it is not considered wise to have the roomstat in a room with TRVs as if they are set lower than the roomstat the roomstat would never reach temp. & shut the ch system down (until the end of the programmer time period did). This would leave the boiler continuing to fire & pump hot water around what may be a loop with largely closed off radiators - inefficient & wasteful.
If you do have TRVs in the same room as the roomstat set them to the Max available - this means that the roomstat (assuming set lower) will take precedence over the TRVs.

Roomstats placed where secondary heat sources are in use are at risk of shutting the central heating system down prematurely for the rest of the building. This is also true of e.g. having the roomstat in a pool of sunlight from a window where solar gain may have an effect on it but not the rest of the room.

Once you have got your head around the above we may start talking to you about flow & return temps to improve efficiency (unless your controls do this automatically) ...

ArthurN

Thank you Buff, for that!
It's always useful to have something explained a different way, as it means a much better chance it's going in :-)
I'm working on this, and tonight is a trial. 
Probably be back on this thread to update in a day or so!
Thanks ever so much, really appreciated.
N