Hi Sam
Welcome to our community.
I’m sure you’ll find we’re all happy and supportive people.
You’re welcome to ask anything during your research.
If it’s specifically about Velbus (rather than a continuation of this thread), either start a new thread or send me a direct message.
Best wishes,
Stuart
Hi, I also look for a solution to replace the controllers for my boiler and 4 zones.
I have a Grant Vortex condensation boiler with a single channel controller and 4 zones, that are controlled by thermostats turning 4 Grundfos circulation pumps on and off depending on temperature demand. This system seems to be cobbled to together by whoever put it in and is not optimal. The boiler I’ve already replaced (it used to be a 20 year old Firebird).
I have 40 radiators and those I’ve already fitted with AVM Fritz!DECT 301 thermostats. There is no wiring at these and there is no easy way to do this either. But I’ve got those integrated in OpenHAB already.
So what I’m looking to replace is the single channel boiler controller, the control of the circulation pumps of the 4 zones and preferable also integrate the control of the immersion with that. All of that should be OpenHAB integrated, yet be able to work autonomously and not require internet or cloud access. I don’t mind, if the wiring to the 4 zone thermostats and the boiler controller have to be revised.
/M
Hi Marlow,
Can you indicate what the wiring is between your current setup?
IE
Is it a bus or radials?
Is it 2 core or 4 core?
Each of the 4 zone thermostat has a 3 core 1.5mm2 230V power supply and then a 3 core cable back to the circulation pump in the press. So it essentially does nothing else than turning the circulation pump on and off based on the temperature in the hallway, where it is situated.
I guess, that could be bastardised into a power feed taken from the one 3 core cable and then using the other 3 core cable going back to the press for data.
The 1ch boiler controller has 4 x 3 core 1.5mm2 cables coming into it. One which isn’t connected, one which is the power feed, I’d presume, one that goes to the boiler and one which I don’t know what it does. I have very little knowledge on these things and only started reading up on it, when we moved to our current place, because the whole system is a mess.
/M
Sounds like what you’re looking for is a way for each Thermostat to trigger (power on) its own circulation pump AND independently trigger the boiler.
You could achieve this by just adding a interlock relay to each Thermostat, the output of these linked together so that as long as 1 relay is closed the boiler will be triggered.
I did some research today, as it’s been bugging me for a while. This place is very old (build 1815) and every efficiency I can get will save me fuel. So I went and traced all the wires.
So, there is 3 core going from each zone thermostat to the press. I have also found out, that the remaining 3 core at the boiler controller also goes to the press.
From what I can see, the way it is wired, is that the circulation pumps only come on, when the boiler controller is feeding power to the boiler (the live to the boiler also is the live to the zone thermostats). The reason, the zone thermostats don’t go off, is because they also have batteries. Neutral from the boiler controller is wired to neutral of the circulation pumps.
Neutral of the thermostats is then wired to live of the circulation pumps.
In theory, I should be able move the entire setup to the press and then be able to make it smart from there using the existing wiring.
/M
Okay, sounds like you have a plan forming
In regards to Velbus, is it possible just to bring the 2 wire data bus around and the power units locally ?
/M
Thank you for asking.
If you can find a way to get 3 cores between each unit / module, then yes, there’s no reason at all why you couldn’t power each part / section / group with a tiny 12 to 18 Vdc supply and switch the 230Vac supplies for pumps where needed.
The actual data bus cable between modules has to consist of :
If you have to run a new data cable, you can use tiny installation grade microphone cable (assuming we’re not talking about very long runs).
For example this 3.2mm OD cable
Or the Van Dammed equivalent.
But if you have to run a new cable, you might as well use a 4 core EIB grade, but I understand your restrictions, so if you can use what you have already in place and just mark each cable core accordingly, you will very probably get a working system easily.
FYI, the ma current requirement for each module is shown on each product’s page of the website.
Let me know if you want any more information.
Good luck,
Stuart
Stuart, you might enlighten here.
Is there an option to push a temperature reading from a third party sensor via OpenHAB to Velbus ?
Lets say, the temperature readout from an AVM Fritz!DECT thermostat or DECT repeater, read that out, let OpenHAB send that info into Velbus and Velbus should then react to this accordingly.
I’ve seen that there are virtual relays. But what about virtual sensors ?
/M
I’m not sure what you’re asking, but the Current Temperature value from a Velbus Thermostat is Read_Only.
With the logic inside the Thermostat working with it.
You can Write the various Target Temperature values to a Velbus Thermostat, but I don’t think that’s what you’re asking.
Again, not sure what you’re asking.
Virtual relays = Items that appear as Full relays as far as logic & functionality are concerned, just without a connection to the outside world.
Virtual Sensors ? What would the point / objective be?
Are you trying to leverage the logic of a full Thermostat by using current room temperature from a different device?
The first generation Thermostat modules supported some kind of outboard or comparative temperature sensor, but that feature was never used by any installer (that I’m aware of) so was not rolled over to the new glass panel units.
Sorry if that’s not the answer/s you were hoping for.
So basically, you are saying, you can only use Velbus temperature probes with the Velbus system. You can not tell the Velbus system from the outside, what the temperature is.
/M
Arrrr
I see where the confusion is…
There’s no such thing as a “Velbus Temperature Probe”, the temperature sensor is built into the glass panels.
So unfortunately, your absolutely correct.
The best the Velbus system could offer in this situation is something I explored some time last year (I’ll try to find the thread).
You could put a 1Kohm thermistor at the end of each cable run into each zone and hook up 4 sensors to a 4 channel VMB4AN input device, which has extremely similar functionality to a thermostat (as in 4 different target points and the ability to affect relays etc)
Update
Here’s the other thread where we explored this as a solution
The issue I am having is, that
a) this is an old building, with old walls, which was completely refurbished about 15-20 years ago.
b) i have cat5e wiring in every room … but they don’t go to the press. They go to an entire different place of the building
c) i’m not going to run new cables across the place, unless they replace an existing run. It’s extremely cumbersome.
d) I already have 100% wifi coverage, zigbee and dect coverage around the place
e) I already have DECT temperature probes in most rooms, which are fully integrated in OpenHAB.
So all I would need to achieve is to read out that temperature and push it to some sort of input, where the Velbus system can react to it.
The VMB4AN module sounds like one step in the right direction.
/M
Arrr, again you can’t push a value into a VMB4AN, you can only read the values, or the output states that the logic inside the VMB4AN decides.
Not really, because of the above.
However… Not to be outdone…
There’s no reason why the Thermostat logic can’t be done in a stand alone openHAB2 / Node-RED instance and push relay status updates into Velbus relays. (Or any other brand for that matter)
It wouldn’t be my first choice, but there are plenty of examples of people using openHAB2 as Thermostats with very advanced timings.
@ThomDietrich Thermostat boilerplate would be an excellent start.
Alternatively, if you want a stand alone Thermostat, where you can create timings per zone and use the Thermistor option, you could do a lot worse than use a Robot Electronics DScript based Ethernet LAN relay board and expand their example Thermostats timer script (in the zip file) to cover as many zones as the relay board can support. (If you’re prepared to explore their programming language, which looks a lot like old school BASIC)
For example, the 2 relay version has 2 inputs for thermistors.
Or the 4 channel version, which has 4 inputs that you can use with thermistors.
The 8 relay version has 7 inputs, but if you wanted to switch 7 pumps and 1 boiler / heat source, based on 7 zones, it could work really nicely.
But if you just want to use the room temperature data from your existing devices, with openHAB2 taking care of the logic, you could opt for a simple Ethernet relay board like this
Which has a nice case
Doesn’t quite work like that.
Essentially, what I want is a standalone system, that operates autonomously. Lets say, the OpenHAB board was not around, it would operate of what’s there. (Velbus relays and Velbus glass panel sensor).
However, when the OpenHAB logic is there, it would be nice to feed extra data in for an more optimised approach.
I guess, in theory, that can be achieved by manipulating the setpoint then.
Lets say, where the Velbus sensor is, it’s colder than the setpoint, but other rooms in the zone have achieved the temperature needed. Or the opposite.
The VMB4AN module is interesting non the less, because it would allow for the Velbus system to control and monitor the temperature of an immersion boiler.
It would also allow to measure the temperature of the hot return feed and only turn the heating boiler on, when that temperature drops there, even though the zone circulation pumps already are on.
/M
Right then…
I see where you’re going with this.
So yes, a combination of Glass Panels and 1K sensors via VMB4AN would do the trick.
I will use this system.
Möhlenhoff alpha 2 Ethernet Bus or Funk
You can read and write Temperature with HTTP binding and
regex.
I haven’t tested it jet but the Manual is quite comprehensive.
Edit:
Official Instructions and XML Guide :
https://www.ezr-home.de/index.php?option=com_content&view=article&id=4&Itemid=3&lang=en
In case anyone is watching this thread, or finds it later.
The Robot Electronics DScript boards with the thermostat and timer script can work totally independently, other than pulling current time from an NTP.
With openHAB2 able to push target temperature updates and switch on and off time sections. (If that’s what you allow / program into the script, {script is maybe the wrong word, as it creates a full web page UI})