I have a Napoleon direct vent fireplace. This season sometimes the fireplace came on in response to thermostat but other times not so I tried two new Honeywell thermostats.
Pilot light stays lit. When I touch white and red thermostat wires together, the fireplace comes on.
When I connect the wires to a thermostat (one old one, Napoleon version that has worked for years and two new ones) and call for flame, nothing happens.
The heat only thermostat has R, W and Y connections. I tried red wire to R and white wire to W. Nothing. I tried red wire to W and white wire to R. Nothing. I tried red wire to R and white wire to Y. The fireplace comes on but does not shut off in response to the thermostat temperature reading.
I tried a more complicated battery operated thermostat that can do both heating and cooling but also can do just heat as for a fireplace. The thermostat responded to my programming instructions. However, I get the same results as the simpler thermostat.