Just relaying an experience in case someone else happens across it. I swapped a 500W baseboard heater for a new 300W unit as part of a circuit balancing act.
Heater refused to turn on, but the digital thermostat seemed just fine. Measured voltage at heater, only getting 200. SHIT, did I puncture/damage wiring when finishing the room? Even at a lowly 200V I figured the heater would turn on (just a simple resistor).
I guess 200V is too low, as it turns out the thermostat was rated for a minimum of 2A (300W is only 1.25A). Bypassing the thermostat temporarily, the heater (now face-down on the floor) is producing heat.
Off to store, purchase a thermostat that is compatible with lower loads. Make the connections, all looks good until I'm screwing the thermostat face plate on. Without warning, the thermostat display goes blank. SHIT! Did I short something out when screwing in the plate? Try again, seems ok but the same thing happens. Can't believe I bought a bad thermostat.
Then it dawns on me...thermal cutoff is activating. Didn't think I'd ever see it, particularly with a little 300W heater. Problem resolved simply by orienting heater in 'normal' position.
This calls for a cold beer....