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OpenTherm Gateway

Is someone presently working on integration of Homey with the OpenTherm Gateway? The gateway proves to be very robust. Would be nice to control my heating via Homey and this gateway.



  • I'm also interested, currently I'm looking into a new heating system, interesting read here: (dutch,a lot, a lot of information) the openterm gateway is mentioned a couple of times there.

  • When I'll get the Homey this will probably be my first project if I find the time. I use the OTGW for about a year now and I am satisfied with the stability (only had to reset it once) and the use (icm Domoticz).

  • @DieterKoblenz, can you please tell me how you see using it?
    At the moment I'm compairing the Honeywell Evohome system and some solution with the Danfoss LC-13 thermostats and RWE Smarthome.

    The Honeywell system is, as I see it, a finished and complete system, but 'locked down'. A system build around the Danfoss thermostats is not really readily available, so I wonder how others are using this and how they will make use of homey. The RWE Smarthome looks ok, but I'm not completely sure about it, partly after reading this: (dutch)

  • Oh you can not compare the OTGW with anything like the evohome or z-wave thermostats across the house.

    As the name says it's a gateway between a regular (modulating) thermostat and an opentherm compatible CH system. Since I have a small appartement with four heated rooms I do not bother with different zones. I use the gateway to keep track on the temperature in the house and it gives me the possibility to overturn the normal program. So when I head home from work earlier I can put up the thermostat to 21 degrees and come home to a nice heated house.

    Its the cheapest solution I could find for internet enabled thermostat control. Advanced solutions like the Evohome go into the hundreds of euros/dollars. If you have a (small) house and don't want to bother with zones ánd you have an opentherm compatible thermostat and CH system this could be a great solution.

  • Ah, Ok, thanks. I am looking into a system with multiple zones, so the only benefit of an OTGW would be for logging purposes then.

  • @DieterKoblenz: did you already start on it? I already ported small part of my Vera OTG plugin code to nodejs. Looked like a nice first app to start with. But if you already have something, I'll start with another app.
  • RamonBaas said:
    No, since I don't have a Homey and don't expect it anytime soon starting another app seemed premature. So please by all means continue with your project. If I ever get a Homey I'll be very happy to use it ;)
  • @RamonBaas : seems you have more code in place than I have, so please go ahead. Looking forward!!

  • To tease you guys a bit 'Athom-style': I'll show some screenshots. This is what I have now (and you won't have for a while :D).

    So a simple settings page and one thermostat device, with which you can change the temperature & see the room temp. Still lots of things I want to add. First of all: sensors (temperature, pressure etc.).

    Seriously: I need to clean the code a bit and then I'll put a simple version on GitHub. Hope to get around to that coming weekend.
  • looking great! Please also consider multi room sensors and settings (to directly control z-wave valves?
  • tunf said:
    looking great! Please also consider multi room sensors and settings (to directly control z-wave valves?
    Not sure what you mean by that... The OpenTherm Gateway does not use z-wave.
  • OTG != multi- room/zone controller.

    OTG only reads communication between one Opentherm thermostat and a Opentherm (gs)
  • DD Member
    tunf said:
    looking great! Please also consider multi room sensors and settings (to directly control z-wave valves?
    You can use flows for this. If the OTGW can override the setpoint, you can use that in combination with Z-Wave valves in a flow to have some kind of zone control.
  • MarcoFMarcoF Member
    edited February 2016
    You are right about the OTG and zones! OTG "only" controles the setpoint and Homey should take control of the zones.
  • Unfortunately, thermostat command classes are not supported (yet): see here.
  • First simple version available (one thermostat & temperature sensors only).

    MilanVanDenMuyzenberg for initial testing!
  • If you have updated to Homey FW 0.8.24, please use the latest GIT version or wait for App version 0.5.2 to be released.

    (They changed the API which broke the app...)
  • Version 0.6.1 has been published. You will need to remove the thermostat device and add it again.
  • OGSOGS Member

    What converter do you use between the OTGW and Homey?
    I can only find a serial or usb version of the gateway on kiwi-electronics. 

  • I've replaced the 7805 by a dc-dc converter and included a USR-TCP232-T in the OTG.
  • OGSOGS Member
    Thanks. I will look into that. 

  • Version 0.6.2 has been published for people using Homey FW 0.9.1. It will only work with that FW though.
  • Works like a charm  <3
  • RamonBaas said:
    Version 0.6.2 has been published for people using Homey FW 0.9.1. It will only work with that FW though.
  • Is it possible to get vars like current setpoint and temperature via an external api? Since you can only open one connection to the OTGW and Homey "owns" it I would like to get those values from Homey

  • RamonBaasRamonBaas Member
    edited September 2016
    @DieterKoblenz Why would you only be able to open one connection? Depends on your ethernet module I guess. I can open 5 connections without a problem.

    Or would you like an API function similar like for the config data, such that you can use:
    api('GET', '/app/com.tclcode.otgw/getOtgConfig/', null, function(err, result) { console.log(JSON.stringify(result, null, 3)); });
  • Hmm, then I will check again in my config. I am using an wireless accesspoint with ser2net and I can only connect one client at a time.

    But yeah, an API similar to getotgconfig would be nice. You get a json response right? At the moment I am getting an not authenticated error even when I am using the bearer token. I checked your source but it says authentication is not required, right?
  • Have a look at e.g. HomeyDash if you want to get to the data outside of Homey.
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