Recommendable wired heating control system

Tags: #<Tag:0x00007fc202258250>

Hi guys,

looking for a recommendation for a central heating control system that manages the valves over wires and is well (=ready made) compatible (=integrable) with OpenHab.

I have 15 radiators - a control wire goes to each - split into 8 zones and a central heating unit (boiler).

I seek wired system = no hassle with changing batteries, no radio interference or too long distance.

I don’t want to control the valves with OpenHab directly - I seek a ready-made system that will control the heating so, for example, I won’t have to program or sort out things like temperature hysteresis within the zones. One thermostat per zone and temperatures managed separately for each of the zone.

And - of course - the system to be open for integration into OpenHab. In this way OpenHab will serve as an umbrella system managing other tasks too but the heating control system will be capable of stand-alone operation.

There is plethora of choices for the wireless systems - I like Honeywell Evo Home for instance. But I insist on going wired way.

For wired solution I found TapHome looking promising - which however is more like less-open and less-customizable OpenHab and not the single-task (well tuned) heating control system.

Happily ready to defend my choices / explain more if questions come but will end here not to make to post too long. Any recommendation for what to look into by OpenHab community? Thanks in advance for any hint.

Good morning,

Have you considered a Velbus based system.

It’ll do exactly what you’re looking for, assuming that you have

  • A 4 core power cable to each radiator actuator.
    2 for power
    2 for ‘valve open’ microswitch - for Heat call

  • 4 core data bus cable to each zone for thermostats, which would be multi function glass panels.

The latest Velbus binding from the maintainer is really good - https://github.com/cedricboon/openhab2-addons/releases/tag/2.5.1.202002010925

The important questions are, where in the world are you and is there already a Velbus distributor near you?
https://www.velbus.eu/sales

Good luck,

Stuart

UK Velbus importer

1 Like

Good morning Stuart,

thank you very much for the reference - and no, I didn’t come across Velbus till today. Looks promising too with few buts…

I do have 4 core cable to every each radiator actuator in the house as well as data cables to each place where the zone thermostat shall be mounted. The power cables aren’t really the 230V types (2.5mm2) but are fit to handle servos in “regular” remotely powered and controlled valves.The installation is ready for Domat control system. However to my knowledge Domat is closed system and not even open to north-bound integration into OpenHab or anything else - so I’m trying to figure out alternatives - with the ultimate goal of bringing all house subsystems under one umbrella “smart” monitoring and management.

Velbus would require a little bit more setup effort than I’d prefer but upon a first view it seems manageable. It is not mono-task (=heating control) only and I haven’t yet figured out how it handles gas boiler (Vaillant) but I guess it’s only a matter of digging into the matter deeper.

The mono-task and “work out of the box” preference for the heating control comes from one ultimate requirement: I want all house subsystems to be standardized consumer solutions that work stand-alone and if the “smart umbrella system” power cable is unplugged the entire house continues to function in the old fashioned way. If anything goes wrong with the smart integration (due to my lack of competence or lack of time to toy around with it) I want very easy way to get (temporarily) rid of it - the way my wife or children will handle effortlessly.

On the positive side Velbus seems like it could take over more tasks than just central heating.

So one of the biggest obstacles may be distribution channel - and maintenance/service/support should anything go wrong. The installation is to be done in Prague, Czech Rep. - and there seems to be no local partner :frowning: Or?

Other than that Velbus seems like fit-for-the-job!

1 Like

There’s essentially no such thing on the market (well, to the best of my knowledge). It’s probably not worth producing such a thing because only very few people are willing to put wires to all radiators when retrofitting.

Very much understandable. Not so many cases of existing house retrofit with a scale big enough so that wires are installed to all radiators without much of an extra effort and yet not making the extra step of redesigning the overall heating and switching to e.g floor heating. But here I am…

On the positive note - both Velbus and taphome seem as viable option = both are wired (!) and both are open to north-bound integration (are open systems).

Both however require more integration beyond out of the box solution for the heating itself. I’m pretty ok with toying around with integration to the umbrella management. But I’d wish for the basic function = centralized heating control to be “ready for use” (plug it in and set the time schedule & temperatures).

I very much like Honeywell Evohome which has a unit controlling the boiler, internet gateway and proprietary tablet handling the settings. Integration into overlay “smart” management is possible. But it is wireless (already now having issues with Somfy IO shades on the most distant window sometimes being inaccessible) and - most important for me - actuators (valves) operating on batteries. Call me crazy but I will not become a slave of replacing batteries in so many smart devices around the house.

There are lot more wired systems controlling heating (just like the already mentioned Domat) however these guys seem to live in the past and completely ignore “smart” world of homekits, ifttts and OpenHabs of these days (somehow I still feel they will however handle the heating control better with so many years of experience) and than there are the new kids on the block - smart, easy to install, wireless and battery operated. Getting a bit too philosophical here… …so if anyone else have any other suggestion I’d be grateful - if not, than be it Velbus or Taphome or Domat (need to see).

Well you eventually can apply an underfloor heating controller system to your radiators.
It’s using essentially disaggregated thermostats, i.e. valve and a thermometer per flooring loop or per radiator in your case.
Disaggregated BTW is an advantage as measurements of a radiator-mounted device are not representing the room temperature well enough.

Hi

I don’t think there is anything out that there that is “easy to setup” and worth having in your home.

Everything I’ve look at over the years require some degree of confusing setup.

To boil your setup down to the very basics.

Put a 4 wire actuator onto each radiator.
(24Vdv or 230Vac, both 3 Watt)

Power pair
Volt free microswitch pair

Back at your cabinet, join all the microswitch pairs together in parallel and connect them to the (I think) Volt free Heat Call terminals on your boiler.

(A simple isolating relay may be required)

So that should any ONE of the microswitches closes, the boiler will be triggered.
FYI, on a safety note, the microswitches don’t close the circuit until each valve is fully open and open the circuit as soon as the valve starts the close.
Which takes about 2 minutes in each direction.

Now join all the 0v / neutral feeds to the Actuators.

Which leaves only the +V or Live feeds for each Actuator.
These need to be connected to individual relay circuits ( IE a channel of a VMB4RYLD )

Next step is to hook up the Velbus Glass Panels in each zone, onto (ideally) a bus / loop / ring data cable.
(You can use radials if you wish, it just makes it messy back in the cabinet, where all the ends need to be joined together in parallel)

  • +15v
  • 0v
  • Data High
  • Data Low

After you get all the Velbus modules powered up, it’s just a matter of using the free software to give them base addresses and name the modules / channels.

The Heater channel of the glass panels just require 1 action to be assigned between it and the respective Relay channel for the actuator for that zone.

Action 0104 - Momentary / Follow - explanation

Any configuration you add after that would be purely to suit your needs.

You could stop there and let openHAB2 define target temperature / mode changes.

Or you can keep all of the scheduling within the Velbus ecosystem, leaving openHAB2 to ‘look in’ to make changes as required.

If you want to add the ability to move the valves once a day, without triggering the boiler, you’d only need to add an interlocking relay between the microswitches and the heat call connection of the boiler, then add a 0104 momentary action between the Pump channels of EVERY glass panel and the interlock relay.
Then activate the Unjamming option in each glass panel configuration.

A detailed generic drawing can be found here.
http://www.mdar.co.uk/dl/Basic_Wiring_plan_V1.5.pdf

For anything more specific to your home / project, please send me a PM.


Any advice offered publicly should be verified with a local tradesperson, to ensure you comply with local regulations.

I can supply specific drawings for a project.


This short video shows the very basics of a Velbus system, including setting up a glass panel as a HVAC thermostat

For sure.
I have radiators AND underfloor heating, both on a Vaillant gas boiler.
My radiator thermostats are wireless (so not what you want) und my underflooring is not an autonomous system as I’d like it to be, that’s mainly because there was no suitable readymade system available when I recently reworked that floor level .
So I went for the disaggregated approach (OH-controlled valves and OH-connected temperature sensors with OH rules as the “virtual” thermostat). That ain’t as failsafe as an autonomous subsystem would be but on the other hand side I need to keep my OH alive and working anyway. Too much comfort we don’t want to miss any more in case it goes down.

Anyway, my solution with the Vaillant boiler was to insert common actuators between the boiler’s heating controller and the pumps that it controlled. It’s like a light with a connected switch that you retrofit to make it smart: the existing control continues to work. But I can override it at any time.
I do so when my ‘virtual’ thermostat calls for heat. If the water temperature drops below an acceptable level, the boiler starts heating on it’s own.
For Vaillant, if you like, there’s an EBus interface from a company called Esara, and an EBus OH binding, allowing for deep integration levels if you are willing to dive into programming.
But you don’t need it. You can essentially apply my scheme with any boiler, it’s working fine AND autonomously in case OH should fail.