OpenHABian as the thermostat

Sorry if this is in the wrong place I just have a quick question. Has anyone tried to control a boiler with the same raspberry pi that is running OpenHABian? And if so have there been many problems with it and how long has it worked without something going horribly wrong and you were left with a boiler stuck on or off? My understanding of the boiler is that it’s on/off and it will run for a bit then stop and wait till the temperature goes up or down. To me it seems like it would be easy to mimic the control of the old thermostat with the gpio binding.

I would never want to make a system like a boiler more complex. There is a reason things like that use very simple mechanical, or super simple encapsulated systems. A crash or power failure, sdcard failure, etc turns your smart home, into a dumb bomb.

You could mimic the thermal relays with the GPIO but that scares me. At the very least you would want an old mechanical thermal cutoff set a few degrees/pressure higher than you would ever set the system with Pi. Cause the way Mr Murphy (law) works, you will inevitably be the first person to have a spectacular failure in a new and exciting way.


To be clear, I don’t think making your boiler smart is a bad idea, I just don’t think making a pi with gpio pins being the only method to turn on/off the boiler being a safe thing to do.

Yeah that makes sense. But to clarify, (I could be wrong) the current thermostat doesn’t control the boiler directly it has 2 wires that feed into it that then go to a switch that has to be flipped on for the boiler to work I know when the power went out last year the boiler system never ran and the thermostat seemed to think nothing was connected. I know that taking apart the boiler and the connecting the raspberry pi is a bad idea but what about just taking those 2 wires and putting them into the gpio? Or was that what you meant was a bad idea?

that I don’t know. If the boiler has it’s own control system that can cut out when it hits xxx limits, and the thermostat connection is for the act of heating house, and everything else is handled internally. That should probably be safe. I wouldn’t use GPIO pins directly, I would use the GPIO to control a dry contact relay instead. I am not a plumber/HVAC guy, My response is based on fear of boilers that have gone bad.

Yes, definitely do this OP - don’t wire direct to the Pi’s GPIO. Keep the electricals separate.