I'm replacing my baseboard heater thermostat with a new Honeywell unit. This is the 3rd one! I have 2, 10 foot 240V baseboard heaters hooked up to a 30 amp breaker. For some reason, I keep burning out the thermos or what I recently discovered is the thermo is getting hot, thus preventing it from kicking on at the desired setting. If the room is 65, but the thermo is overheating and "feels" 90, then naturally, it won't activate. So, I have the 2 power legs coming in and the 2 white wires from each heater tied together at the box and the 2 black wires from each heater also tied to together at the box. Each "line" wire connnected to the thermo and each 'load" line (white and black) connected. I noticed it will initially work, but then overheat. The black "load" wire where I connected it to the thermo had melted some of the insulation. Ok guys, what is going on here?? Is my thermo not rated for the type of load? It's rated for 5280 watts @240V and 22Amps. I'm going nuts!! Thanks!

I think the issue may be the rating of the stat. If the manufacturer's instructions or stamped on the stat itself do not say 'Rated for 100% of the listed rating" or something to that effect, then the maximum load the stat can handle is 80% of the listed rating, which would be 17.6 amps.

The two 10 foot heaters you have should be 2500 watts each, for a total 20.8 amps.

We usually use a low voltage (24 Volt) stat, or a 1 pole 120 volt stat, to control a contactor that actual switches the line voltage for 30 amp heating circuits.

Beyond that being the problem, I usually have a mental block when someone tries to describe how a circuit or wiring is connected, so, just to be sure, is it possible for you to show a sketch of exactly how the stat is connected?

Before I confirm or deny the stat is wired correctly, I really need to understand how it is connected.