Tado Controller, Opentherm Gateway, Navien Oil Combi Boiler.

For OpenTherm-gateway related questions in Domoticz

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roycruse
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Tado Controller, Opentherm Gateway, Navien Oil Combi Boiler.

Post by roycruse »

Sorry this is a long post, but its a complex issue / question so need to get all the info I have so far out there.

Hi, I'm new here and don't currently have Domoticz but I understand this is the place to find opentherm gateway experts...

I recently fitted a Navien LCB700 Oil Combi boiler. and originally had it hooked up to my Google Nest thermostat using opentherm. This worked fine giving me the ability to control my central heating and my hot water.

I wanted more control over my house's central heating, specifically I wanted rooms other than the main living room to be able to call for heat if they needed it. So to this end I purchased a Tado kit including the opentherm wireless receiver, 6 smart radiator valves and a couple of wireless room stats.

Ever since connecting the Tado up for the first time my Navian boiler has thrown a ton of Opentherm Comms errors (Navian code 783-00) and flashed red on the front screen - the boiler also does wired stuff like start up when there's no demand for heat from either the hot water or the heating. As a result I've had to use my boiler on manual mode or switch back to the nest.

After getting no where with Navien and Tado support over a few weeks I decided to start debugging the issue myself. So ordered an Opentherm Gateway from the Nodo Shop.

When I connect the opentherm gateway in "gateway" mode the Tado/Navien combo works perfectly... so I switched the gateway to "monitor" mode and straight away back to the same errors as if the gateway was not there.

So question number 1 is when in "monitor" mode does the signal get passed on exactly as is at the same voltages etc?

So I get my oscilloscope out and measure the signal without the gateway in place for both Tado and Nest. It turns out the Nest Low voltage is 6v and the Nest High voltage is 16,8v so within the opentherm spec. When I check the Tado though its Low voltage is 7,2v and its High voltage is 15,4v so the low is just outside of spec and the high is just within spec.

So question number 2 (my main question). What is likely to be the reason I'm seeing a non working system when the tado is connected directly or via the gatewway in "monitor" mode. And I get a fully working system when I connect it up via the gateway in "gateway" mode.

is it likely to be the slightly out of spec voltages and my boiler is sensitive to them but the gateway is not?
OR
is it likely to be that in "gateway" mode some of the opentherm messages are getting manipulated as per the documentation on the otgw,tlcode website that's causing the system to work ?
OR
is it something else I'm not understanding ?

I have logfiles and images but they are too big to post here and i cant post a link.
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waltervl
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Re: Tado Controller, Opentherm Gateway, Navien Oil Combi Boiler.

Post by waltervl »

I think you are mixing up the forums. As mentioned by the designer of the otgw on http://otgw.tclcode.com/index.html#feedback the support forum for the otgw is
https://www.domoticaforum.eu/viewforum.php?f=75
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roycruse
Posts: 2
Joined: Thursday 14 September 2023 9:56
Target OS: NAS (Synology & others)
Domoticz version:
Contact:

Re: Tado Controller, Opentherm Gateway, Navien Oil Combi Boiler.

Post by roycruse »

Sorry i was given a direct link to this forum by the guy who runs Nodo-Shop where I bought my gateway ? perhaps he mixed it up - is there no knowledgeable opentherm tech guys here in this forum then ?
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waltervl
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Re: Tado Controller, Opentherm Gateway, Navien Oil Combi Boiler.

Post by waltervl »

Perhaps, give it some time.... But it does not hurt to put this message also on the other forum.
Domoticz running on Udoo X86 (on Ubuntu)
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