High Limit Switch used in many gas & electric heaters. Commonly found on older Hurlcon and Astralpool heaters.
Used on outlet for some early Hurlcon & Purex Minimax heaters. Automatic Reset.
Other High Limit (Hi Limit) Switches:
42-45C° Inlet Hi Limit (Hurlcon, Astralpool, Raypak, Pentair)
52-55C° Outlet Hi Limit (Hurlcon, Astralpool, Raypak, Pentair)
60C° Outlet Hi Limit AGS (Hurlcon, Astralpool, Raypak, Pentair)
70C° Outlet Hi Limit (Hurlcon, Astralpool)
100C°
175C° Flue Temp Sensor (Hurlcon, Astralpool)
Hurlcon / Astralpool HiLimit Locator Brass Threaded Plug
AKA Thermal Cutout