Poor man's thermostat

Hi Everyone!

I was wondering if the Shelly 2.5 can be used (in conjunction with a home automation system like homeassistant and some temperature sensors) as a "thermostat" of sorts.

My HVAC system is a single phase heat only forced air furnace. It currently feeds 24VDC to a thermostat (the one I want to get rid of), so I was hoping I could feed the Shelly 24VDC from the furnace to the "L" port, then "N", "01" and "02" to C (COMMON), SW1 to G (FAN), SW2 to W (HEAT).

Does that make sense?

Thanks!

Thanks for taking the time to reply 66er !

I'm not clear on how to wire this, so let me take a step back and ask you and everyone else here if you know of a case where the Shelly 2.5 was used to control a furnace, water boiler, or any other heating device, and more importantly how the cabling is done.

Thanks again!

Zitat

can you please draw a little sketch, that can help me understanding it better.

I'm not sure I can do that cause that's exactly what I'm asking for.

I can give you a general idea though:

My HVAC system is a forced air furnace. I'll call it furnace from now on cause it doesn't have an AC unit.

The furnace now controlled by an Ecobee thermostat. I want to replace the Ecobee thermostat with a combination of one Shelly 2.5 and zigbee temperature sensors around the house. The shelly will be used to control the HVAC (heat on, fan on, heat off, fan off, both on... etc.). The home automation platform I use (home assistant) will tell the shelly to close and open the two relays in the shelly 2.5 based on current temperature and/or a set schedule.

The Ecobee is powered by a 24 volt cable coming from the HVAC (labeled "R"), so I figured I could connect that cable to the "L" port on the shelly. Then I would connect the "C" or "common" cable from the furnace to the "N" port on the Shelly, closing the circuit. This should power the shelly with 24v.

Do you see where I'm going with this? Since the shelly is running with 24v, I thought it should be able to relay 24v to the other two ports, and I would connect one port to the "G" or "FAN" terminal on the furnace, and the other one to "W" or "HEAT".

So what I want to know is if the general idea I'm explaining here can work, and how the cabling should be done.

Thanks!