Dry 120V relay for low voltage circuit

Hi all,

I am looking to ‘smartify’ my gas fireplace, which I currently control with a wall switch connected to the low voltage circuit of the fireplace (voltage generated by a thermopile, haven’t measured it but from what I’ve read its normally 300-700mV DC).

The easiest way I see to do this would be to buy a smart lightswitch (Lutron, as it will integrate into my existing system), then use a relay to control the low voltage circuit, so the change would go something like this:

In theory I don’t see why this wouldn’t work, I am just not sure how to select the right relay. From what I understand something like this would work:


But I want to make sure the 120V won’t connect to my low voltage thermopile circuit and fry it/the wiring.

Most things I read about use the low voltage to switch a higher voltage, but in this case I want the high voltage to swtich the low voltage. I also read about the Zwave ZFM-80 but I don’t have a Zwave hub and quite frankly would like a setup where I can theoretically change to whatever switch in the future and still have a functional setup (because the relay will be separate.

If not that relay then maybe something else on this list? https://www.digikey.ca/products/en/relays/solid-state-relays/183?FV=a40155%2C1fc006b%2C1fc0505%2C1fc0511%2C1fc1216%2C1fc0037%2C1fc192d%2C1fc1e65%2C20800ed%2Cffe000b7&quantity=&ColumnSort=1000011&page=1&pageSize=25

First time relay buyer as you can tell… :S

Thanks in advance for your help! Any input is appreciated.


Everything on this forum will pertain to using a SmartThings hub, which is a z-wave hub.

kinda renders the whole exploding-house-thing moot

Wow that’s my bad. Granted I am a rube to smart home stuff when you search for smart home diy forums this comes up first and is described as a community for exactly that, not knowing it’s a brand I thought it was more of a generic forum. My bad guys sorry to waste your time