I have a Superior SSDVR3530CNM gas fireplace, which I'm trying to find a proper thermostat for.

The manual recommends this one:

enter image description here

However, it doesn't seem like they are sold anymore. (Or I'm not searching the right way.) It also recommends a couple of remotes, but I don't like how they look and the ones that I found for sale were like $150, which I think it's a bit expensive compared for what you can get for that money from a 'regular' thermostat these days.

There's a wiring diagram and a snippet from a troubleshooting guide, which suggest that it's a 24V thermostat which can be installed instead of the 'optional switch' that I do have on the wall: enter image description here enter image description here

The problem is that I'm not sure whether it's any 24V thermostat (which most of them seem to be these days) or it has to be somehow 'gas-fireplace-aware' (e.g. not to switch on and off too often or something like that).

So, the question is -- do I just pick a random 24V thermostat from Amazon and it should work? Or is there any other considerations I need to take into account?

  • You need a millivolt thermostat, as suggested by Jimmy Fix-it below. A 24 volt thermostat will not work.
    – Tester101
    Sep 19, 2016 at 10:58

1 Answer 1


The information you supplied in your question seems contradictory. A millivolt thermostat is specifically different then a 24vt thermostat.

I would suggest you look for and confirm the existence of the referenced "low voltage transformer" and confirm whether or not it is part of the thermostat circuit loop (and confirm its voltage). If it is there then the 24vt thermostat is what you need.

Alternatively a "Thermopile" as referenced is a very low voltage electricity generator heated by the pilot. If that is the power source for the gas control valve and thermostat then you need a millivolt thermostat.

  • 1
    Also, 24 vt.thermostats often have a "deadband" feature that allows you to adjust the response, ie. control how quickly it responds to setpoint (turn on-off frequency). Sep 19, 2016 at 4:10

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