I'am installing a 240v heater which has a built in thermostat.I am hanging it from the garage ceiling.To adjust the thermostat you either have to be 8' tall, or use a ladder every time you change the heat setting. So I got a 240v line thermostat to mount on the wall. My question is, can you run 2 thermostats together? The heater has a fan delay, to stay running when the heater shuts off to cool the heating element. Can I turn the heater thermostat all the way up, and control the heater with the wall thermostat?
I don’t know the model you have but I do this in my plant all the time, the ones I use the fan is on a thermal snap switch so it doesn’t matter if the heater is calling for heat or not. I bypass the OEM stat as the ones I have purchased that stat fails in a year and a half anyway. I have a 1/2 dozen running on line voltage cadet thermostats works great for our small shipping container shops.
Because the heater wants to run the fan after the set temp is reached, you should do the following (we will assume celsius temp, since there is no location for the OP).
Set the heater thermostat to 20°. Set wall thermostat to off, heater does not come on. Set wall thermostat to 25°, heater comes on, heats to 20°, heater shuts off, fan continues to cool heater. If temp drops below 20°, heater comes on, etc. When no longer need heater, turn wall thermometer back to off when heater is not on.