When we moved in, our natural gas fireplace worked well: Flick the switch & it would ignite.
Years later, it started acting erratically: Sometimes, the switch worked, other times, no luck. We'd try turning the switch off & on again a few times ("Hello, IT. Have you tried turning it off & on again?") and occasionally that would get it going.
Most recently, the workaround hasn't, & the burners fail to ignite 100% of the time. The pilot is fine.
Knowing the fireplace doesn't use the house power (we could use it even during an outage), I figured the voltage was low enough for me to troubleshoot. I disconnected the switch and tried to turn on the fireplace by carefully joining the conductors. This worked 100% of the time. So, I believed the fireplace was OK and decided the switch needed to be replaced.
Since I had it open already, I immediately installed a spare switch I had lying around. This worked well at first, turning the fireplace on & off 100% of the time on that first day. However, the next day, it was acting up again and failing most of the time.
I'm thinking it worked that first day since I'd warmed up the fireplace by connecting the wires, and subsequent attempts that immediately followed, using the new switch, could take advantage of the higher starting heat that generated just enough voltage. However, once the fireplace cooled to the pilot-only ambient temperature the next day, it wasn't enough voltage.
What kind of switch, exactly, should I be getting to fix this? I checked our big-box hardware stores but their switches all seem rated for typical 120V+ use. I spotted thermostats in the fireplace section, yet no switches. Where, generally speaking, might I find what I'm looking for? I'd prefer just a wall switch, and I don't want to call somebody in to fix this.