Automated radiator valves

[paulca]

Hi,

Does anyone know of any "smart" radiator valves which are 'hackable', ie. can be used without getting locked into one system or other?

I gather most will have 433Mhz (in the UK) RF receivers and respond to some signal or other.

What I need are valves which people have successfully worked out the protocol for, so I can write an interface using some form or Arduino or RPI RF module.

So far I have come up short on finding this and the best option currently open is mains operated valves switched with a smart relay.

[paulca]

This is about the best I have found so far.
https://community.openhab.org/t/any-trv-suggestions/36723/20

Mostly the mains operated values for underfloor heating, which fit radiators.  It does mean running mains to the radiator I want to switch, but the advantages are no batteries to change and no proprietary "smart home" system to integrate with.

[capt bullshot]

Most probably not applicable for your country:
I'm using the "Fritz" branded (made/sold by AVM) valves, controlled by the (in Germany at least) popular "Fritz Box" router. They need the said router, but don't need any cloud service, and are controllable through an API provided by the router.

Otherwise, yes these thermal expansion based valves you mentioned are IMO the best choice if you're willing to run the cables.

[stevelup]

Honeywell EvoHome with the HGI80 USB gateway would be my recommendation.

Works fine with Domoticz etc., and the protocol is well documented. No third party cloud services involved.

See section 3.3 here:-

https://www.domoticz.com/wiki/Evohome#Adding_Evohome_via_usb_device_.28HGI80_or_equivalent.29

[paulca]

So the fritz stuff is extremely expensive.  A single radiator valve in £75 on UK amazon.

The Domoticz stuff looks like an attempt to harness and control smart home systems from a Linux based web UI, which is a cool idea but a bit heavy handed.  Feels like using a sledge hammer to crack a nut.

Both are effectively end solutions and probably very good ones, but I need component, near the metal access.

What I'm really after is very simple. 

Turn valve on.
Turn valve off.
etc.
and a way to determine which valve I'm referring to.

Ideally, if not wildly expensive, turn valve 25% on.

I could make the thing for £30, but it would be big, ugly and have bits growing out of it.  Maybe I should consider buying (a cheap) one and ripping it guts out and soldering in an ESP chip.

As a ramble to why I want such low level access is because, generally speaking, these smart home devices are usually pretty damn simple things and the smarts comes in the software and architecture.  However, in doing it myself I can get 100s of times more functionality because I can hardcode things that will take a big company months to write and release a UI for.  Even installing a basic and fairly open wifi device these days involves pairing processes and config pages, UIs etc.  Months of work.  I can just edit the C file or Python file and change my SSID and PSK in 5 minutes and move on.  I don't intend for it to be usable by anyone else.  Although I might share the code for reference.

In software development 90% or more of your time is wasted making your software pretty and idiot proof and you usually lose 90% of the possible functionality along the way.  </rant>

[nctnico]

How about industrial motor controlled valves. http://jpfluidcontrol.com/product/bw/
If the heating system has individual tubes going to each radiator then you can put the valves in the closet where the distributor is located. That way the valves are out of sight.

[NiHaoMike]

Or lower the water temperature and then add fans to selectively enhance the air circulation around the radiators.

[stevelup]

Maybe I should consider buying (a cheap) one and ripping it guts out and soldering in an ESP chip.

This would probably be your best bet. But an ESP chip isn't going run on 2 x AA batteries for over a year like the Honeywell valves do...

I think you're slightly underestimating the ingenuity that goes into a product like that. It needs to transmit a huge amount of torque into a tiny spot whilst being quiet enough not to wake you at night and power efficient enough to not need new batteries once a week...

I think perhaps I wasn't perfectly clear as to why I sent you the domoticz link though - that was merely to show that you can directly control all the Honeywell hardware if you buy the USB bridge. You don't need domoticz - but you can certainly use the source of their Honeywell direct control library as the basis of your own project. It's well refined and complete.

Also, the firmware is hard baked into the Honeywell peripherals. They can't be firmware updated and so the protocols can, by definition, never change. You won't have to reinvent the wheel because someone changes something somewhere in the future.

[paulca]

Interesting points Steve.  I had forgot about power consumption.  No 2xAAs would not run an ESP for a year.  Probably a day or a week if I got the deep sleep stuff working properly.

I'll look into the USB bridge.  It's probably a bit expensive to just buy to try though.  Not sure how much the rad valves are but the gateway seems hard to find.

Something is leaning me towards mains operated valves, they are cheap and easy to control.  Of course it means running mains flex along the skirting boards.

[Jeroen3]

Underfloor heating usually already has a heat exchanger with a pump. Can't you enable/disable this pump?

Also the mechanical part of the thermostat valve is ~€20, while the analog temperature part is also ~€20.
So €70 for a digital valve is not that bad.

DIY you might be able to use a linear actuator on the mechanical part of the valve. Or maybe a solenoid if strong enough.

[paulca]

Underfloor heating usually already has a heat exchanger with a pump. Can't you enable/disable this pump?

Also the mechanical part of the thermostat valve is ~€20, while the analog temperature part is also ~€20.
So €70 for a digital valve is not that bad.

DIY you might be able to use a linear actuator on the mechanical part of the valve. Or maybe a solenoid if strong enough.

It's not for underfloor heating, I just found the mains operated valves in that section.

Analogue TRVs are a fiver (£5).  https://www.columnrads.co.uk/logic-15mm-angled-trv  I'm sure better ones are more expensive, but my plumber quoted me £10 fitted.

[nctnico]

I'd stay clear from the cheap TRV valves. They don't work at all so don't waste your money on these. Just buy the ones from Danfoss. If you shop around a bit you'll find these aren't extremely expensive.

[paulca]

I'd stay clear from the cheap TRV valves. They don't work at all so don't waste your money on these. Just buy the ones from Danfoss. If you shop around a bit you'll find these aren't extremely expensive.

To be honest, TRVs are useless anyway.  In my last place the TRVs were good quality, but all they did is regulate the temperature right beside the radiator.  The valve it connecting to the radiator by heat conducting metal.  So as soon as the radiator gets hot the valve gets hot and shuts off.

This will work absolutely fine if you want to run your heating 24/7, but personally I switch it off when I'm out at work.  So when I come home the house is cold, the heating comes on and the TRV shut the radiators off 5 minutes later, long before the house warms up.    If the heating is left on over a much longer period things will balance out, but it is much cheaper to warm the house up with 30 minutes of full blast heating first which the TRVs interfere with.

Usually they just stayed on MAX or OFF.

This is why I want to move to a decoupled system with a temperature probe that is not near the radiator and a remotely controlled valve.

[Jeroen3]

This is why I want to move to a decoupled system with a temperature probe that is not near the radiator and a remotely controlled valve.

You know there are other ways to manage temperature? Varying the temperature of the water based on the outdoor temperature and sunshine. Whilst the final bit of room regulation is done by thermostat valves. It works like this in many offices, and if you buy a smart thermostat it will also attempt this based on weather data.

[paulca]

This is why I want to move to a decoupled system with a temperature probe that is not near the radiator and a remotely controlled valve.

You know there are other ways to manage temperature? Varying the temperature of the water based on the outdoor temperature and sunshine. Whilst the final bit of room regulation is done by thermostat valves. It works like this in many offices, and if you buy a smart thermostat it will also attempt this based on weather data.

If you have a boiler that supports it AND you only need ONE temperature to satisfy ONE demand.

Also I'm fairly sure that very, very few smart thermostats support that and I know that most boiler do not.

There is an approach which I know people use which it to turn the heating temperature way down and leave the heating on, much much longer.  However this is bit of a damp squid when you consider how much electric a boiler and circulation pump uses.

[langwadt]

This is why I want to move to a decoupled system with a temperature probe that is not near the radiator and a remotely controlled valve.

You know there are other ways to manage temperature? Varying the temperature of the water based on the outdoor temperature and sunshine. Whilst the final bit of room regulation is done by thermostat valves. It works like this in many offices, and if you buy a smart thermostat it will also attempt this based on weather data.

if you lower the water temperature won't the valve just open more?

you can get trv valves with a remote sensor head

back in the 80's my dad installed a system that used a power resistor next to each trv valve to turn down the heating

[Nauris]

if you lower the water temperature won't the valve just open more?

you can get trv valves with a remote sensor head

back in the 80's my dad installed a system that used a power resistor next to each trv valve to turn down the heating

For example Danfoss RA2912 with 2 m capillary tube. Not too expensive and avoids any unnecessary electronics.

[paulca]

I'm not trying to buy a system off a shelf.  I'm a software engineer with a life long dream of automating my home and now I own it I intend to do it DIYWO - Do it  your own way.

I'm sure HoneyWell, Danfoss, Alexa, GoogleHome, <insert a dozen other data farms here> do a great job in most circumstances and I realise that most, 99% of users wouldn't even question the features and if they did they wouldn't know what to do with them.  But I'm in the 1%.

For example.  The one of the reasons for motorized rad valves is "multi-zone presence awareness" using "BLE radar" and other means.  So a room when unoccupied might have a temperature it aims to achieve, if it's at that temp the valve can close, but if I enter the room, the valve might open and the target temperature might rise.  Say a base temp while I'm in the house (mobile's MAC detected on the Wifi) is 18*C for all rooms, but the bedroom being the warmest room in the house is already there.  That radiator does not need to come on.  However if the probability of my presence in a the living room is published to be greater than 66% the target temp might be 21*C and the heating system will sort it out.  When I leave it's target temp goes back to 18*C.

Things can become very complicated with multiply layers of schedules and demands and because I don't have to produce a UI for it or a manual that can be understood by a 65 year old silver surfer customer ... and make it basically idiot proof... I can make it as complex as I want/need/like.

To do this, however I need "near metal" access, not integration with someone else's hub/router/gateway/trojan data farm.

[nctnico]

I'd stay clear from the cheap TRV valves. They don't work at all so don't waste your money on these. Just buy the ones from Danfoss. If you shop around a bit you'll find these aren't extremely expensive.

To be honest, TRVs are useless anyway.  In my last place the TRVs were good quality, but all they did is regulate the temperature right beside the radiator.  The valve it connecting to the radiator by heat conducting metal.  So as soon as the radiator gets hot the valve gets hot and shuts off.

The ones from Danfoss don't have this problem because the heat sensitive capsule is decoupled from the valve and it has openings to allow airflow:


I have these in my entire house and they work as a charm. I tried a cheaper one on a radiator I added myself but quickly realised that was a mistake.

[paulca]

Its still going to regulate the temperature beside the radiator which will slow the heating's ability to warm the house as it will switch the valves off simply because it's 22*C beside the radiator when the rest of the room is barely 18*C.  Yes, yes I know you can tweak and fiddle with them to find where you want it set, but the point still stands they are rubbish at being a room thermostat.

Some of the HoneyWell ones, for what ever reason, probably not having to buy a separate temperature probe, measure the temperature beside the radiator, in the valve itself, and use that in the feedback for the valve.  So they will "learn" that the near-radiator temp needs to be 28*C for the room to get to 22*C and will adapt accordingly.  However the only reason for doing this is to save the cost of a temp probe.  Then again, how can it learn the room temp without having a temp probe anyway.  Makes no sense, except to be able to sell a radiator valve product for £60 when a £20 one would have done.

EDIT:  Maybe there is slim possibility this would prevent overshoot.  If you wait until the room is 22*C before shutting the valve by the time the rad starts to cool it's 24*C, but there are better ways to deal with that.

For me a temp probe costs about £3.50, although that does not include the price of the 5V power supply.

Nor do they (Danfoss TRV) meet my requirements as there is no automated remote control of them.

[nctnico]

Its still going to regulate the temperature beside the radiator which will slow the heating's ability to warm the house as it will switch the valves off simply because it's 22*C beside the radiator when the rest of the room is barely 18*C.  Yes, yes I know you can tweak and fiddle with them to find where you want it set, but the point still stands they are rubbish at being a room thermostat.

Trust me, not the Danfoss ones...

But I think your plan is not going to work. It takes long to heat a room and a boiler doesn't work very efficient at high power. You will be much better off with keeping the rooms at a standard day / night temperature. Heating a room costs more money than keeping it at a steady temperature. Also turning the heating on once you enter the room means you'll be too late. The walls will be cold  for a long time and make the space uncomfortable to be in. If you want to safe money on heating then get better insulation and use floor heating. Floor heating is much more comfortable to begin with at lower temperatures. If you mount the hoses directly under the floor tiles instead then it will heat up quickly too.

[paulca]

Installing underfloor heating will cost me about £10,000.

My heating control system is a lot more complex than I'm really describing here.  For example, concepts such as pre-ramp and ramp down. 

Detail TBC, but something like:

"Base" temps or "never below", 24/7 365 15*C  (or 2*C in the garage when it's heated)
Higher base temps on schedules, say, Mon-Fri 7am to 8am, 5pm to 12pm at 18*C.
My phone is on the Wifi: 20*C
My phone is in a room: 21*C

I also have other forms of heating to heat the rooms most used independently with a small electric heater (fake fireplace) rather than running the heating to heat one single room I can have it aim for 22*C in there and let the rest of the house fall to 20*C or some rooms fall to 18*C as I like my bedroom cool and I don't really care if the kitchen is that warm.  So I would be running a 2Kw electric heater instead of a 30Kw boiler.  Assuming I close the doors to that room.

It doesn't really matter if I later discover it doesn't work, that will be part of the fun and I can adapt and tweak it.  If I buy a system, get it all properly installed to come close to what I think I can DIY it will cost me thousands and even then if that particular system turns out not to work "for me", I'm  out another chunk of cash and hassle to change it over to another or trying to cross-integrate multiple systems.

For example on the software and comms side, I could have went straight to MQTT etc.  But I choose not to.  My basic "data fabric" is simple, modular and distributed enough that I can easily tag an MQTT relay into it, would take me an evening.

It's also so simple it just wouldn't work as a "product" system or even an OSS project.  It would be too hands on and too hard to adapt to another individuals needs, unless you were the one who wrote it of course, when it becomes really simple.

[Jeroen3]

You have not enough respect for those little thermostatic valves!

Yes, they are near the radiator. Yes, this will have a slight effect. If you don't like that, get one with an remote sensing element. They exist! Fully passive!
No, they won't turn off because it's over 22 degree. They are a lot slower than that. True, tuning them is tricky, but so is a DIY PID solution.
Thermostats are not simple on/off devices anymore.
Also, the radiator will create natural airflow, which will provide airflow around the sensor. You shouldn't place things on top the radiators, such as desks.

...

If you have a boiler that supports it AND you only need ONE temperature to satisfy ONE demand.

Also I'm fairly sure that very, very few smart thermostats support that and I know that most boiler do not.

There is an approach which I know people use which it to turn the heating temperature way down and leave the heating on, much much longer.  However this is bit of a damp squid when you consider how much electric a boiler and circulation pump uses.

Yes, the heater needs to support it. I don't know about what heaters are common abroad, but here Nefit and Remeha gas heater are supporting this for decades. It's called modulating.
Also yes, the thermostat must support this. Usually one comes with the heater, otherwise a Honeywell Lyric or Nest will help you.
The cost of heating water electrically does not change. Pipe loss maybe, but the energy is the same. The heater is inside your house, so theoretically 100% efficient. The loss will be in the insulation around your boiler.

...

if you lower the water temperature won't the valve just open more?

The valve will open longer. If your house is sufficiently insulated the frequency of temperature instability will be lower, and you will be closer to the requested temperature. More comfort.
If you're pumping 60C water through the radiators every 30 minutes it will be degrees over, then degrees under the requested temperature. When the same temperature can be maintained by pumping say 40C for a while as well. For gas heaters, this is cheaper.

[paulca]

In my locale I have never seen a boiler that support less than 60/65*C.  All the boiler radiator output thermostats I have had go from 60/65 to 85*C.

If it did support 40*C I expect by the time you had pumped that around 10 radiators it would be completely cold by the time it gets to the last few.  Of course if you leave the heating on for 4 hours it will eventually heat up to 40*C across the system.  This is probably fine if you are accepting leaving your heating on 24/7, but I am not prepared to heat my home 24/7 continuously when I'm very often out for 10-12 hour periods during the day.  If I shut the heating off while out at work for 10 hours, then 40*C will take hours and hours to raise the temp back up.

On the efficiency of this; the efficiency of a house is basically the ratio of heat in, to heat out over time.  The warmer the house the more energy it losses.  This is the basic thermal transfer equation, the same as mosfet datasheets.  So trying to keep the house at 20*C all day will just mean it pumps more energy out into the environment.  Allowing it to go cold when not occupied and then boost heating it when I come home, seems to me to be far more efficient.  I could be wrong though.

The electrical use of the boiler is a consideration, maybe you miss understood me, but when ON it will consume power to run fans, valves and the radiator re-circulation pump.  So it will go from, probably 0.5W when off to 250W when running.  Running that 250W load all day, even if the burner is only firing every few minutes is wasteful.

I don't mind the temperature fluctuating by a few degrees by alternating the heating on/off.  In probably 95% of homes in the UK the heating runs HOT 60-80*C on a 7 day timer which get adjusted to increase or decrease the length of time it's on.  Usually this adjusting of the schedule is manual.  As spring weather warms up the two blocks of 2 hours in the evening becomes too much, so you shorten them to 1 hours and in summer you remove both completely.

Even then you usually don't get it perfectly right, weather variations etc. and that is why most heating controllers have "+1" and/or "ADVANCE" buttons to manually force the heating on earlier or for longer.

All I initially intend to do is add temperature awareness to those kind of schedules which will switch the boiler off if the target temperature has been approached.

[Jeroen3]

I start to realize we have very high tech heating systems over here.

If it did support 40*C I expect by the time you had pumped that around 10 radiators it would be completely cold by the time it gets to the last few

You have series connection? If you system even able to have radiators closed?

Anyway, the point is not to always pump 40C, but start at 60 and then keep 40 to maintain comfort. But I assume this is not possible with your system.
250 Watt for pump mode is quite high. Maximum electric power of my heater is 85 Watt.

But I suspect there aren't any electric valved cheaper than ~70 pounds. Maybe a true industrial solenoid, but the clunking sounds all around the house might not very relaxing.