The Raypak 018304F Auto Reset Limit Switch is a factory-set high-limit safety component designed to protect compatible Raypak pool and spa heaters from excessive temperatures. It monitors the heater’s operating temperature and automatically interrupts the safety circuit when the fixed 150°F limit is exceeded. Once the temperature returns to a safe range, the switch automatically reset... https://www.partshnc.com/018304f-raypak-auto-reset-limit-switch-fixed-150-f