Robotic radiator valves

[DavidMellor]

Hi group,
I'm trying to choose a robotic radiator valve and would like to ask what the group might recommend please?
I am just starting on my smart home adventure. I've been a programmer using C for around 25 years and have a preference for getting low level and giving myself maximum control but would also like to get up and running quickly.
I am thinking about Home Assistant as a quick solution to get up and running and perhaps look at development libraries like open Z-wave later, and any others I might need depending on the devices I end up working with. I would use a raspberry pie or other small form factor computer.

On the radiator valves then:
I'm a blind person so can't see the pictures of any devices on the web. I'd like to ask if they have numbers printed on them like conventional TRVs, in which case I'm wondering if they have a second built in motor to adjust the head so the selected temperature is still correct after it's been adjusted by software.
I could use wired or wireless communications.
I'm picturing something that is much the same size and shape as a conventional TRV if there is such a thing, rather than an over-sized blocky device with a flip up display designed to show scheduling information, etc.
It does need to be able to integrate with a computer setup then rather than being part of a proprietary self contained system.
There would ideally be some means of adjusting the temperature with the valve itself rather than resorting to a computer or phone but that's not essential.
Later I will look for a relay that I can use to turn the boiler on and off.
The valve does need to tell the computer/controller that the room has reached its desired temperature, or better, that the room isn't getting any warmer.
If the room isn't getting any warmer then the boiler shouldn't stay on for the sake of that room although the valve could still remain open if it's not reached the desired temperature.
I am keen to avoid filling my home with EMF anymore than I absolutely have to, so would not choose to use WIFI as the means of communication.

As a last resort I could use under floor valves, or if unwise to put such things out of sight could put them in an airing cupboard or loft space and have a dedicated flow pipe for each radiator.

Very many thanks for any guidance,
David

[DanD]

Hi David,

I can recommend the Honeywell Evohome system with its HR92 radiator controllers and boiler control. However, this system is proprietary, but it is possible to integrate it into the home automation software Domoticz. It uses a proprietary 868MHz protocol to communicate. The HR92 radiator controllers only have one motor which controls the valve and there's an LCD display showing current setpoint or temperature. Local control is all handled via a rotating control on the top of the device which is similar to some manual TRVs, but has an additional confirmation button below the rotating control, just above the LCD display (the LCD display is hinged and can flip out). There are no audible confirmations on the HR92 device. The system also has a central touchscreen controller, but this also doesn't have any audio accessibility features as far as I'm aware. I can't comment much further on the system's accessibility, except to say there are Honeywell Android/IOS apps and more recently limited control via any browser has also been added and all these will offer some form of spoken feedback.

Let me know if you need any more info and I'm sure others can also provide more details on the Honeywell system.

Dan

[DavidMellor]

Hi Dan,
Thank you very much for providing so much information.
I've come across the Honeywell system a few times on the web.
My big concern here would be the lack of ability to integrate with my own software.
I wasn't expecting any kind of special accessibility features though. Speech software with a PC web interface would be enough.
I'd like to continue looking for information about less proprietary systems that are easier to integrate.
Again, very many thanks,
David

[HenGus]

Hi Dan,
Speech software with a PC web interface would be enough.
I'd like to continue looking for information about less proprietary systems that are easier to integrate.

David

You can control Evohome with Amazon Alexa.

[DavidMellor]

It's the addition of door/window sensors, presence detectors, even door locks and a precise control over the logic that hold the whole thing together that would be important to me. If the window is left open or there is no one detected in the room I want to turn the radiator valve off.
Perhaps the controller that Dan mentioned would do these things but there is a lot of money invested in something that has so little flexibility in my view.
Home Assistant initially on a raspberry pie with a bunch of Z-wave, Zigbee, bluetooth devices etc is really the direction I want to move in.
The DIY approach is not going to be everyone's thing unless they're programmers.

[DanD]

Hi David,

Maybe the Danfoss or Heat Genius Z-wave radiator controllers might be a better choice if you want a more open system from a programming perspective. I don't have any personal experience using either of these devices, but they are a similar size to conventional TRV controls and have an LCD display on the top along with 3 control buttons. Hopefully others can comment who've used some of the Z-wave radiator controllers.

PS If you change your mind about Evohome it'd be great to get you involved in the further development of its Domoticz integration .

Dan

[top brake]

... Speech software with a PC web interface would be enough.

Evohome has both integrations. Voice throughout alexa and pc web interface through TCC login. The API is available to developers of the main ecosystems

[StuartP]

Home Assistant initially on a raspberry pie with a bunch of Z-wave, Zigbee, bluetooth devices etc is really the direction I want to move in.
The DIY approach is not going to be everyone's thing unless they're programmers.

If anyone's interested I have some StellaZ valves, brand new in the box that I never found the time to build into a DIY system, ended up with Evohome and associated bits.

[DavidMellor]

Very many thanks Dan and others for your comments.

I need to spend some time reading reviews.
One thing that confuses me is the way Z-wave devices sleep for so long to reserve power. I wouldn't have guessed that it would take much power to just sit and listen for radio traffic. I would have thought the operation of the motor would have taken far more power.
From some Amazon reviews, if a rad valve is on all the time it would last 24 hours. If it wakes up every 5 mins it could last 3 months.

Very best wishes,
David

[dty]

The motor does take more power than the radio; but that doesn't mean the radio only take a little power!

Listening for (digital) traffic is quite expensive. It's not like passively tuning in an old AM radio. You have to try and extract bits from the noise, synchronise on the bit rate, match against preambles and headers, etc. all to discover that you were just listening to noise.