Controlling central heating (HVAC) through X-10

Post by **Bwired** » Sun Nov 12, 2006 11:54 pm

With the interface I am describing above and the with the complete opentherm protocol I think you can completely control a opentherm heating system. So for example if my Home automation system puts on the heating I can see it directly on my thermostat (heating on) and the other way around. Pushing the buttons on your thermostat is like sending opentherm commands to your heating system. My thermostat (Nefit)is reacting to opentherm commands. It's still theoretically of course but I think and hope it will work this way for me.

Pieter Knuvers
www.bwired.nl Online House in the netherlands. Domotica, Home Automation.

Post by **MindBender** » Mon Nov 13, 2006 12:12 am

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Bwired
 I think you can completely control a opentherm heating system.<hr height="1" noshade id="quote"></blockquote id="quote">No, you cannot. You can control your boiler, but only at a very low level; You can read the temperature of the returning water, you can control the burner and he pump. At this level you need to implement your own thermostat, which is very complex.

You could use a standard thermostat and manipulate the information on the bus, but the your boiler would need to listen to 2 masters, making it - if it works - very ineffecient.

The way to go is really to control your thermostat, preferably through OpenThem. And I think the Remeha gateway is the easiest solution.

Post by **Bwired** » Mon Nov 13, 2006 12:24 am

HI Robert,
Let's see..... I'm not completely sure yet

. I have the opentherm protocol in a document, that it will be difficult I agree fully. I already have the interface (RS232) which goes between the thermostat and the heating system. Just for the record I would be very happy with the functionality you already have at this moment, but I have the interface and want to try that first.

Pieter Knuvers
www.bwired.nl Online House in the netherlands. Domotica, Home Automation.

Post by **Bwired** » Thu Dec 13, 2007 4:12 pm

Hi all,
The Germans are also very busy with opentherm and "Haustechnik"
See this topic for lot's of information about opentherm and what they are doing with it.
http://www.haustechnikdialog.de/forum.a ... otokoll%20

Post by **Snelvuur** » Thu Dec 13, 2007 4:23 pm

Hehe, you found that link because of the referrer link right

For the not so german people here (like me, or too lazy)

http://www.google.com/translate (cant put the complete link in, doesn't work)

// Erik (binkey.nl)

Post by **Bwired** » Thu Dec 13, 2007 5:12 pm

Right, I check my log files for interesting stuff and domoticaforum is linked on that forum

Post by **gason** » Thu Dec 13, 2007 8:07 pm

i am realy happy to help you get more visitors in your forum.
it would be nice to get some answers to my questions in other tread

may be it will be helpfull for all of us.

Post by **MindBender** » Sat Apr 05, 2008 8:51 pm

I have finally started to analyze the protocol used by the Remeha GateWay and I have made some good progress: I have figured out the basics of the protocol and I have reverse engineered 4 datagrams now. That's enough to send a new setpoint temperature, read the setpoint temperature, the room temperature and the outside temperature. I can also read a lot of status info, such as the boiler's water temperature, the output percentage of the burner etc.

Soon I will make a test-program and from there I'm thinking about a HomeSeer plug-in. But first I would like to get the protocol complete. Not because I need all of these datagrams, but because I can

Post by **Bwired** » Sat Apr 05, 2008 10:11 pm

Great progress!
Do I understand you right that you can set a setpoint, the setpoint is directly displayed on your thermostat and the Hvac turns on, if the setpoint is higher then current temperature. Once the temp is reached the hvac switches off again.

Post by **MindBender** » Sun Apr 06, 2008 2:05 pm

Yes, that's correct. Basically I already can do all the things I need to do: Set the desired temperature, read it back and read the current room temperature. The benefit of doing it this way is that all the internal cleveries of the thermostat are still being used so maximum efficiency is achieved.

But I'm not finished yet. Now I know how the protocol works, I'd like to figure out the meaning of the rest of the datagrams: It seems to contain a wealth of information such as burn rate, water temperature etc.

The next step is to write a test program to read out the data myself. After that I'm planning on turning it into a HomeSeer plugin, if that's not too much work. I planned to start today, but I seem to have misplaced my VisualStudio DVDs somewhere...

Post by **Bwired** » Sun Apr 06, 2008 6:01 pm

Great functionality, your choice for a Remeha HVAC system paid off!

Post by **MindBender** » Sun Apr 06, 2008 6:10 pm

Yes, but no thanks to Remeha, unfortunately. I mean; I'm very happy about the quality of their products, but they are still telling people that controlling it remotely using the Gateway is not possible, while the opposite is proven now.

Post by **Bwired** » Sun Apr 06, 2008 8:49 pm

True but they made the gateway with the RS232. What we usually see is that companies don't want to tell there protocol and the way there system works. I have the same experience with Nefit. Nefit would even not let me buy the interface, so I had to obtain it otherwise. Wy not inform Remeha

Post by **Mhwlng** » Tue Apr 15, 2008 2:34 pm

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by MindBender
 I have finally started to analyze the protocol used by the Remeha GateWay and I have made some good progress: I have figured out the basics of the protocol and I have reverse engineered 4 datagrams now.
<hr height="1" noshade id="quote"></blockquote id="quote">I just installed the same hardware (Connected to an AGPO heater)

the remeha program works ok with my heater..

Could you please show the datagrams you already figured out.
That would save me a lot of reverse-engineering work, implementing this in girder...

Thanks,

Marcel

Post by **MindBender** » Tue Apr 15, 2008 3:04 pm

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by mhwlng
 [quote]Originally posted by MindBender
I just installed the same hardware (Connected to an AGPO heater)
the remeha program works ok with my heater..<hr height="1" noshade id="quote"></blockquote id="quote">
So you're using a Remeha Celcia 20 thermostat and a Remeha Gateway to control a different brand of boiler? I know it's supposed to work because it's all OpenTherm, but still I'm a bit surprised.