Tekmar Integration and Add-on

I’ve created a custom integration for Tekmar (tekmarnet) networked thermostats, setpoint, and snowmelt controls with tN4 or tN2 communications using the Gateway 482. This is a local push integration, so it does not work with Tekmar devices that use wifi or cloud, only wired tekmarnet.

The integration uses a companion add-on to communicate with the Tekmar Gateway 482 over RS232. The add-on can run on the same Home Assistant installation as the integration, or they can run separately. I’m running mine separately since my Home Assistant system is located in a different part of the house from my gateway running on a Pi 3 A+ with USB serial adapter connected with wifi.

The integration can be added using a custom HACS repo or manually into custom_integrations. The add-on can be added through the add-on store by adding its repository.

Integration:

Add-on:

A list of compatible equipment can be found here:

Nice! Do you have any insight on if this will work with the new Boiler Control 294? That unit seems to be the new form factor that will replace the 482 gateway.

The 294 doesn’t have a serial port and doesn’t support the tekmar automation protocol, so no it will not work. Much like the 486 only supports “cloud” with no local interface the 294 appears to be the same path as the 486 (I have a 486 too and it’s useless for HA integration).

I haven’t seen anything that says the 482 is being discontinued.

Do you have any idea if this integration could work without a thermostat device and just going off of a device that’s connected via Modbus?

I’m sorta figuring this out as I go but the main thing is I’m trying to have my Daikin mini split heat pumps controlled by home assistant. Currently it looks like my best path is to get these: https://myvrvdrive.com/static/cf1acb87aa34d548b12e2cd5daf6036a/AZAI6WSPDKC-S21%20Product%20Flyer.pdf

And the connect that to a 482 which then I could connect to HA.

There’s two ways I can get the mini splits connected to the 482, either through the 557 thermostats connected to the DKN Plus interfaces directly, and then the thermostats connected directly to the 482.

This option leaves some control of the heat pump out of the loop because the third party thermostat controls for the DKN plus only have Heat, Cool, Fan controls, No louvre position or mode.

But if I connect the DKN plus directly to the 482 through Modbus, it seems like I should be able to control everything on that unit. I just don’t know how I could verify if that would be possible.

Any thoughts for me? Appreciate anything you could offer. Thanks for your work on this integration.

No, the Tekmar 482 is not compatible with modbus. The two protocols are completely seaprate.

Home Assistant has a modbus integration, just use that for native modbus devices.

Has anyone actually tried to probe the 486 or reverse engineer or MITM the protocol from the local network?

I checked mine with nmap, it didn’t have any open ports.

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Thanks. Tekmar is also confirming that I need to pick between the 482 with local serial integration and the 486 with remote apps and no API. I am pretty much stuck with the 486 so the installer gets remote diagnostic access.

If that ever changes in the future I have my 486 to test with to update the integration. I don’t have it connected full time since I’m using the 482.