Hey everyone! I installed a relay on my forced air furnace last year to power a fan when my Ecobee thermostat requested humidity, but it ended up blowing the thermostat. The relay I used was an OMRON G7L-2A-TUBJ-CB, which pulls 2.5 watts when activated. Now I'm looking to install another relay, but I'm hesitant because the recommended models from Ecobee (White-Rodgers/Emerson 90-360 or 90-380) also pull over 2 watts. I have a decent understanding of volts, amps, and watts, but I'm a bit lost when it comes to ohms and relays. Before I connect anything, I want to make sure I understand what went wrong with my first setup. Any advice?
2 Answers
To avoid blowing your thermostat again, consider using a MOSFET and a flyback diode to control the relay. This way, your thermostat won't have to provide any current. You can even find these as complete modules by searching for "Arduino relay". Just a heads-up, if your thermostat is run by AC, the setup will differ compared to a DC one. Here's an example circuit that might help you visualize it.
Just so you know, Ecobee is indeed an AC thermostat, so you might need to adjust your setup accordingly.
Make sure to clarify the voltage and type (AC or DC) of the relay you previously used and the ones recommended by Ecobee. The details can really impact how everything works together. If you can, include some links to those parts to get better advice. It’ll help us understand the whole situation!
Thanks for the quick response! I'll definitely check that out. I think the power comes from my furnace but it seems like the Ecobee can't handle it.