otmonitor hangs

[MarcEberhard]

Hi Schelte,

thanks for the analysis! I have an offer to get a thermostat posted to me on loan, so I will try that next then.

All the best,
Marc

[MarcEberhard]

Hi Schelte,

got a thermostat on loan now.

Connecting the thermostat directly to the boiler works fine. I can see water temperatures, outdoor temperature, water pressure, all there.

Connecting the thermostat via the gateway gives the following output in minicom:

Code: Select all

OpenTherm Gateway 4.0a10
T00030000
T00030000
T00030000
T00030000
T00030000
T00030000
T00030000
T00030000

No reply is received from the boiler and the thermostat does not display any information from the boiler.

What do you suggest as the next step?

Thanks,
Marc

[hvxl]

I'd put the gateway in monitor mode (GW=0) with both thermostat and boiler connected. Apparently you have access to a nice oscilloscope. Does it have the ability to handle two input signals? It would be interesting to compare the voltages on X1 and X2. In monitor mode the signal from the thermostat should go nearly transparently through the gateway. There will only be a slight delay caused by the opto-coupler.

Since you didn't find any signal coming back from the boiler in your previous tests, and the boiler properly responds when the thermostat is connected directly, it would seem that the signal is somehow different enough for the boiler not to understand it anymore.