Do you hear clicks when you move to other positions?

I asked that question because I think that the thermostat is a rheostat and adjusts between low and hi. In other words, I do not think that you have a 3 position switch.

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We replaced ours with the Mysa smart thermostat and it has been fantastic.

The solution is likely to replace the thermostat. Use caution as it is quite likely your thermostat works on line voltage, so there would be 240V present on the wires there.

>I think that the thermostat is a rheostat

Definitely not. If it was a rheostat it would be a power controller, not a thermostat. If it is a resistor, it is a low wattage potentiometer which controls an electronic circuit that senses temperature. Many electric thermostats use bimetallic strips which have an adjustable biasing spring or other means of adjusting the set point.

> I replaced our main thermostat which was pretty simple so guessing this would be about the same amount of work.

Sorry, that's not necessarily true. A furnace thermostat is a third party device designed to be replaced easily and uses low voltage standardized connections. Electric baseboard heater thermostats are usually line voltage high current devices that are double pole if used on a North American 240V circuit. Without seeing the model number (potato quality pic), or the wiring it isn't clear whether you have a low voltage or line voltage thermostat. If you are capable of safely replacing an outlet, you can probably replace this thermostat. The Honeywell Home CT410B is an example of what you may need.

That is not a 3 position switch. It’s a thermostat, without a temperature scale. Turn it all the way counterclockwise (off). Then slowly clockwise until you hear a slight click. That’s the thermostat clicking on as you reach the current room temperature. Continue to turn clockwise 1/4”. This will be slightly warmer than the current temperature. It’s very sensitive. 1/4” is a large range, you’ll want to barely nudge it to adjust temp. Mark your desired level with a sharpie and you’re good to go.

This guy heats

They're only going to kick on if the room goes below the temperature set on the thermostat

Let’s be clear about something. There were power thermostats. There may still be. There were also things that were switches, without thermostat elements, Like a Off-Low-High power mode switch.

What type you have shown is not clear to me.

If you have a professional look at what you have, they could bring considerable information.

If it does not work the way you want it to, then they can tell you better how to achieve your goals.

A smart thermostat and interface module ( power relay ) make almost any level of control possible.

Edit, addition.. I think you have a line voltage control element, so use great caution⚡️⚡️⚡️

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Key words to focus on: high current and safely replacing

Stelpro makes a thermostat that can be controlled remotely using the smart things app. Not quite Nest level but for baseboard heaters they are awesome.

It doesn’t have 3 settings. It has infinite settings from cool to hot. Turn it to low, when you get cold slowly turn it clockwise until it clicks. That’s when the heater turns on. Wait either for the room to warm up or it to click off. If you are still cold, turn it just a little more clockwise until it clicks again. Repeat until you are comfortable. Then out a mark with a sharpie where it’s at.

That is a line voltage (240v) thermostat with probably 20-30a breaker. If you have never done wiring before, this isn’t a project to learn on, since 240v can hurt pretty bad compared to a 120v light switch or outlet. Your main thermostat was probably a 24v low voltage, low current system and is pretty safe for you to work on. Mistakes are more likely to damage the furnace than you. But if you know all the steps to replace light switches safely…this is just a 240v switch that opens and closes itself based on temp.