If this is the case there will be no power to run the smart switch unless it is battery powered.
Gas fireplace switch wiring.
If the fireplace is a 120v control then in most cases you will need a neutral.
It shows the parts of the circuit as streamlined shapes and also the power and signal links in between the devices.
It s probably just a matter of finding a switch with a low enough on resistance.
All the switch is doing is making or breaking a connection it is not wired up to standard 110 volts.
Crimp the connectors securely to the wires.
A wiring diagram is a simplified traditional pictorial representation of an electric circuit.
Assortment of gas fireplace wiring diagram.
A generic low voltage switch from a electronics store or ripped out of a toy would probably do it for example a 12v spst.
The thermopile in your fireplace puts out millivolts nothing near the 120v the light switch was designed for.
When attempting to automate a fireplace with a smart switch you have a problem because a lot of switches require a neutral wire to be connected so they have constant power for the zwave radios to send and receive signals.