Author Topic: Central heating thermostat  (Read 3005 times)

Re: Central heating thermostat
« Reply #25 on: October 23, 2018, 09:29:01 pm »
a slightly devious method of obtaining almost fully independent control over all your radiators (for peanuts) is as follows:

-Install conventional TRVs on all the radiators

- Install a plugtop mains timer near each of the radiators that gobble energy (high power output in parts of the house that are not used often)

- use a simple plugtop DC supply to drive a small heater, eg about 2W rated.  A suitable 5W resistor glued to a piece of metal will do it.

- attach the heater to the wax capsule on the TRV

Set the timer so that the small heater is 'on' when you want that radiator inhibited, and override the system when you want the radiator to be hot.

The way it works is that when the TRV capsule is heated by the small heater, the TRV closes more easily than normal. Depending on the ambient temperature and the heater power, the radiator can be shut off at a lower power and/or lower temperature than normal.

Obviously you can do clever things with fancy timers (which can be interrupted and then resume their normal program) and remote controlled mains sockets and stuff like that.

cheers

Re: Central heating thermostat
« Reply #26 on: October 24, 2018, 07:39:30 am »
When we moved into our new house we realised that the builders had made a right mess of the thermostat zones.  So I bought a number of small programmable TRVs to replace the standard.  They can be programmed with multiple on/off sessions per day, different programs for each day, etc.  They have now lasted 5 years with about 4 battery changes and work very well.  I will probably move to Nest/Hive/etc when the stop working.

tiermat

  • According to Jane, I'm a Unisex SpaceAdmin
Re: Central heating thermostat
« Reply #27 on: October 24, 2018, 07:52:59 am »
a slightly devious method of obtaining almost fully independent control over all your radiators (for peanuts) is as follows:

-Install conventional TRVs on all the radiators

- Install a plugtop mains timer near each of the radiators that gobble energy (high power output in parts of the house that are not used often)

- use a simple plugtop DC supply to drive a small heater, eg about 2W rated.  A suitable 5W resistor glued to a piece of metal will do it.

- attach the heater to the wax capsule on the TRV

Set the timer so that the small heater is 'on' when you want that radiator inhibited, and override the system when you want the radiator to be hot.

The way it works is that when the TRV capsule is heated by the small heater, the TRV closes more easily than normal. Depending on the ambient temperature and the heater power, the radiator can be shut off at a lower power and/or lower temperature than normal.

Obviously you can do clever things with fancy timers (which can be interrupted and then resume their normal program) and remote controlled mains sockets and stuff like that.

cheers

Devious, urm maybe

Completely fucking insane, yes.

Pointless, most definately.
I feel like Captain Kirk, on a brand new planet every day, a little like King Kong on top of the Empire State

Re: Central heating thermostat
« Reply #28 on: October 24, 2018, 08:02:18 am »
I confess, I find the inevitable positioning of TRV somewhat amusing. Where would the best position be to monitor the temperature of the room? On the floor, next to the rad? Possibly not. I like the idea of the remote controlled TRV, but I suspect they would add little to the overall comfort and (here, at least) are not likely to be used in a way  that will save fuel and money. Rooms we use, we heat, rooms we don't are switched off. The underfloor in the kitchen being several inches under screed and tiles has thermal inertia meaning rapid changes just don't happen.

Something Ian referred to earlier though, was the idea of balancing a system: tuning the return valves so that all rooms heat equally. I wonder how many have bothered doing that? (or even, knew it would be a benefit)

Re: Central heating thermostat
« Reply #29 on: October 24, 2018, 08:37:13 am »
I've not seen any in the UK that I can recall, but in several European hotels the TRV has had a capillary tube to a remote bulb, just to get it some distance away from the radiator. 
We are making a New World (Paul Nash, 1918)

ian

  • fatuously disingenuous
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Re: Central heating thermostat
« Reply #30 on: October 24, 2018, 11:54:55 am »
Something Ian referred to earlier though, was the idea of balancing a system: tuning the return valves so that all rooms heat equally. I wonder how many have bothered doing that? (or even, knew it would be a benefit)

We made the service guy from BG do ours. Took him about two hours of running between rooms...

Other than that we don't really fiddle. I'm not sure there's a lot of point in keeping some rooms cold. All the TRVs upstairs are set low on the grounds that heat rises from the lower floor. With no closed doors, heat spreads anyway, so there's little point in substantial differential heating. The ground floor is mostly open plan, we have a big open living/dining room space with the mezzanine/remote command centre opening out into it via an open stairwell. It seems more sensible to heat the entire house anyway unless you're literally living in a single room. If you have teenagers or cats, you're unlikely to keep doors closed anyway.

Anyway, the result is a fairly even temperature throughout. We leave a window open a tad in the spare room but we dry clothes in there and the dehumidifier usually kicks out enough warm air to make up the difference.

It's a happy medium and frankly a lot less hassle than the zillions of controls and options we had in the last place. But I admit I'm the sort of guy that just wants stuff to work with minimal intervention.

My use case for internet-enabled thing would simply to turn it on and off remotely rather than rely on a timer. If we're heading home early in the winter months (probably because we've been stomping around the country in the cold rain for several hours) it would be nice to kick in the heating early. We don't have the benefits of any other heat source  (I have 'fond' memories of being a child and fighting my sister to get in front of the gas fire). Same for the hot water. Also, I'm always forgetting to turn things off when we head off on various travels.
!nataS pihsroW

Re: Central heating thermostat
« Reply #31 on: October 24, 2018, 12:16:06 pm »
Something Ian referred to earlier though, was the idea of balancing a system: tuning the return valves so that all rooms heat equally. I wonder how many have bothered doing that? (or even, knew it would be a benefit)

We made the service guy from BG do ours. Took him about two hours of running between rooms...


SOP isn't it? The primary means of balancing is to make sure the radiators and the pipe runs are sized correctly so the radiators are likely to see the correct amount of flow, but there are always tweaks to be made.  Everyone's needs (and everyone's houses) are different. 

FWIW on the continent they think we are all mad in the UK. They build houses with vastly better standards of insulation, with ventilation systems that have heat exchangers built into them, and heat them (to a more or less constant temperature, not just twice a day) using boilers that are (by UK standards) absolutely tiny.  A 5kW boiler is a common type for a good-sized family home.



Devious, urm maybe

Completely fucking insane, yes.

Pointless, most definately.

your opinion. As pointless as programmable TRVs...?  I may tell the chap that cooked up that scheme you said that. He will die laughing probably.

cheers

Kim

  • 2nd in the world
Re: Central heating thermostat
« Reply #32 on: October 24, 2018, 12:20:03 pm »
FWIW on the continent they think we are all mad in the UK. They build houses with vastly better standards of insulation, with ventilation systems that have heat exchangers built into them, and heat them (to a more or less constant temperature, not just twice a day) using boilers that are (by UK standards) absolutely tiny.  A 5kW boiler is a common type for a good-sized family home.

Yes, but our houses and government are owned by rich Baby-Boomers who don't give a stuff about gas bills or the environment.
To ride the Windcheetah, first, you must embrace the cantilever...

Re: Central heating thermostat
« Reply #33 on: October 24, 2018, 02:08:07 pm »

FWIW on the continent they think we are all mad in the UK. They build houses with vastly better standards of insulation, with ventilation systems that have heat exchangers built into them, and heat them (to a more or less constant temperature, not just twice a day) using boilers that are (by UK standards) absolutely tiny.  A 5kW boiler is a common type for a good-sized family home.


That's rather a sweeping statement I think. Not ALL European countries do that by any means. And some houses over here are built like that (my Dutch colleague lives in one such dwelling in Milton Keynes, which also has solar PV. It was two days before they noticed their boiler had failed to restart after a power cut.).
We are making a New World (Paul Nash, 1918)

tiermat

  • According to Jane, I'm a Unisex SpaceAdmin
Re: Central heating thermostat
« Reply #34 on: October 24, 2018, 02:21:38 pm »

your opinion. As pointless as programmable TRVs...?  I may tell the chap that cooked up that scheme you said that. He will die laughing probably.

cheers

Close personal friend are you? Thought not.

My point was around the idiocy, or pointlessness, of the process you described, not about the use of TRVs, which I have installed at my house.
I feel like Captain Kirk, on a brand new planet every day, a little like King Kong on top of the Empire State

ian

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Re: Central heating thermostat
« Reply #35 on: October 24, 2018, 02:38:45 pm »
For some unapologetic gender stereotyping (it's true I tell you), it's a boy thing. A woman, placed in charge of the design and implementation of a device will install a simple on/off switch and move along.

A boy, on the other hand, will look at the on/off functionality and design a control panel with three dials, six buttons and two LEDs with a removable faceplate. On being asked how to turn the device on, the instructions will be: turn dial 1 to 4, dial 2 to 6, and leave dial 3 at zero. Hold buttons A,B, and D simultaneously until you hear a 3-second beep and the second LED lights up and then turn dial 3 to 2 and dial 1 to zero. If you hear a two-second beep, keep holding buttons A, B, D and also C until the two-second beep sounds and LED 1 lights up. Then turn dial 2 to 10 and the other dials to 0. If the LED 2 lights up and there are two two-second beeps, then remove the faceplate and use a type of screwdriver you don't have to turn the actuator one quarter turn clockwise and then replace the faceplate and repeat to turn the device on. For more information, please consult the badly translated Chinenglish manual that we've included on a 3 inch CD that would not have played even when people had optical drives.

Of course, you will have the modern alternative of an app with myriad options, so you can be frustrated remotely. And this is why men shouldn't be put in charge of anything. They'll just festoon it with needless buttons and options.
!nataS pihsroW

Re: Central heating thermostat
« Reply #36 on: October 24, 2018, 03:50:48 pm »

your opinion. As pointless as programmable TRVs...?  I may tell the chap that cooked up that scheme you said that. He will die laughing probably.

cheers

Close personal friend are you? Thought not.

My point was around the idiocy, or pointlessness, of the process you described, not about the use of TRVs, which I have installed at my house.

Actually I was best man at his wedding. [BTW these days he runs a company making stuff that is so complicated that most folk don't begin to understand it].   It is/was as pointless as programmable TRVs (as chrisbainbridge happily reports using upthread) , which you couldn't then buy. These days you can get them with not only built in timers but with Bluetooth connections too.  The point is that you can easily build something (from bits and pieces you might have lying around more or less) that does the job if you put your mind to it, and you don't have to drain the system to fit it either.



tiermat

  • According to Jane, I'm a Unisex SpaceAdmin
Re: Central heating thermostat
« Reply #37 on: October 24, 2018, 08:10:58 pm »
Brucey, one of you is lying, or older than you let on.

The TRV was invented, by Danfoss, in 1943....

I'll just leave that, there, shall I?
I feel like Captain Kirk, on a brand new planet every day, a little like King Kong on top of the Empire State

Re: Central heating thermostat
« Reply #38 on: October 24, 2018, 08:16:47 pm »
Brucey, one of you is lying, or older than you let on.

The TRV was invented, by Danfoss, in 1943....

I'll just leave that, there, shall I?

But when were programmable TRVs invented?

For reference (my selective quoting):-

...It is/was as pointless as programmable TRVs (as chrisbainbridge happily reports using upthread) , which you couldn't then buy.

I'll open the bidding with 2012, from https://en.wikipedia.org/wiki/Thermostatic_radiator_valve

Quote
As of 2012, electronic TRVs are becoming available which use electronic temperature sensing, and frequently contain programmers so that individual radiators may be programmed for different temperatures at different times of the day.
"Yes please" said Squirrel "biscuits are our favourite things."

Re: Central heating thermostat
« Reply #39 on: October 24, 2018, 11:25:45 pm »
seems reasonable to me. It was many years before that when the thing described was done.

  Still working BTW...

cheers

Kim

  • 2nd in the world
Re: Central heating thermostat
« Reply #40 on: October 25, 2018, 12:21:38 pm »
seems reasonable to me. It was many years before that when the thing described was done

And presumably still pissing away electricity.  A couple of watts for the heater, plus the inefficiency of the wall wart (which is probably linear, if it pre-dates programmable TRVs), plus the power consumption of the timer (which is surprisingly high for the mechanical ones as were common in that era), multiplied by the number of radiators soon adds up.

Okay, that's a win compared to heating rooms unnecessarily, but an electronic valve with an actuator that only draws power when changing state is going to be a substantial improvement.

Of course, then you have to balance the cost of running an inefficient thing vs replacing it with a more efficient new one.
To ride the Windcheetah, first, you must embrace the cantilever...

Re: Central heating thermostat
« Reply #41 on: October 25, 2018, 12:37:16 pm »
People really should also be considering installing external compensators for the efficient running of their boilers. I understand that HMG is consulting on making them compulsory for new installations. (unless they have already done so).
Get a bicycle. You will never regret it, if you live- Mark Twain

Re: Central heating thermostat
« Reply #42 on: October 25, 2018, 12:47:16 pm »
I'm surprised anyone crazy enough to come up with such a scheme bothered with the wall wart rather than just wiring the mains directly to the resistor.

(maybe I've watched too many Big Clive fun-with-mains videos)

tiermat

  • According to Jane, I'm a Unisex SpaceAdmin
Re: Central heating thermostat
« Reply #43 on: October 25, 2018, 01:25:45 pm »
People really should also be considering installing external compensators for the efficient running of their boilers. I understand that HMG is consulting on making them compulsory for new installations. (unless they have already done so).

Not yet, and our boiler was installed last weekend!
I feel like Captain Kirk, on a brand new planet every day, a little like King Kong on top of the Empire State

Re: Central heating thermostat
« Reply #44 on: October 25, 2018, 02:39:37 pm »
seems reasonable to me. It was many years before that when the thing described was done

And presumably still pissing away electricity.  A couple of watts for the heater, plus the inefficiency of the wall wart (which is probably linear, if it pre-dates programmable TRVs), plus the power consumption of the timer (which is surprisingly high for the mechanical ones as were common in that era), multiplied by the number of radiators soon adds up.

Okay, that's a win compared to heating rooms unnecessarily, but an electronic valve with an actuator that only draws power when changing state is going to be a substantial improvement.

Of course, then you have to balance the cost of running an inefficient thing vs replacing it with a more efficient new one.

fair points all, but I don't think you have taken into account all the factors;

a) it was only done on a couple of radiators
b) the system only needs to run for about five months a year
c) the PSU was an efficient inverter type
d) the timer was electronic (with a battery backup)
e) the heater is (of course.... ::-)) timed only to run when that CH heating zone is 'on' but that radiator isn't needed; typically this might be a couple of hours a day.

  The radiators concerned were large ones in cool spaces that were not needed at all times when the rest of the system was 'on' typically in either the morning or the evening.  IIRC when those radiators were 'on' they comprised the bulk of the load on the boiler after the system had been on for half an hour or so.

By my reckoning each heater used one or two units of electricity per year (plus whatever it took to run the timer which can't have been much, in any event it was hardly "pissing away electricity"....) , took about three-quarters of an hour to dream up and fit, and saved at least £100 per year in fuel bills for the boiler.  I think that was pretty good value. 

cheers

Mrs Pingu

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Re: Central heating thermostat
« Reply #45 on: October 25, 2018, 05:31:43 pm »
People really should also be considering installing external compensators for the efficient running of their boilers. I understand that HMG is consulting on making them compulsory for new installations. (unless they have already done so).
As mentioned up thread I think they sound like a good idea.
I'd like some other people to try it out first though, I've learned my lesson about being an early adopter.
Do not clench. It only makes it worse.

ian

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Re: Central heating thermostat
« Reply #46 on: October 25, 2018, 06:10:08 pm »
To be honest, unless you have the elite skillz to do it yourself, or have a well-fed pet gas appliance installation engineer, does anyone trust any kind of boiler and controls will be installed right? I think every house I've owned and lived in has suffered from one kludge. More things is more things to do wrong.

In The Asbestos Palace, facing the arduous task of properly fitting the flue with screws and brackets and stuff, he (and I'm sure it was), opted to wedge it in place with a random bit of wood.
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Aunt Maud

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Re: Central heating thermostat
« Reply #47 on: October 26, 2018, 05:17:50 pm »
Snip.......it's a boy thing. Snip.... And this is why men shouldn't be put in charge of anything. They'll just festoon it with needless buttons and options.

Speak for yourself, it's On/Off for me.

I can't be arsed with all that technology pissing around app bollocks.

Re: Central heating thermostat
« Reply #48 on: October 30, 2018, 04:58:09 pm »
Ooops - I posted this on a different thread:
The thermostat in our house has had a broken LCD display forever, and is now out of warranty and >100 to replace.

I've been instructed to sort it out however I see fit, so now I have carte blance to install something I like, with the proviso it has to work well and be sorted soon (so no roll-my-own - would take until domomsday). The house is 3 stories - generally the ground floor (office) is freezing, the middle (the living area and kitchen, also where the thermostat is) is reasonable, and the upstairs (bedrooms) is too hot! Dumb radiator valves don't solve the issues because we only really need the upstairs heating in the morning, and the middle and ground floors heating in the evening.
The current front runner is Tado (mainly because you can do the smart thermostat thing first, and then go for smart radiator valves later). Has anyone got any experience (good or bad) or using Tado?

ian

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    • The Suburban Survival Guide
Re: Central heating thermostat
« Reply #49 on: October 30, 2018, 05:18:32 pm »
I did book a Hive installation for the reasons mentioned. I think I might leave the old disconnected thermostat on the wall so the in-laws can adjust it as they please and hide the actual thermostat upstairs. It sort of works in the hall now, but probably not the best place as it has two radiators (plus the downstairs loo) and no external walls.

The cats will hate us once we start turning down the heat when we're out in an evening (Bad Cat likes to sleep suspended between the back of the sofa and the windowsill, her belly soaking up all the heat).

Anyway, three-week wait for the installation but tbh, I can't get too excited by a new heating thermostat. Oh I've tried.
!nataS pihsroW