while the plastic cap is for protection during installation

This solenoid is rated for operation in ambient temperatures up to 155°F (68°C)

It automatically resets (closes) when the temperature cools down to 130°F

Universal Refrigerant Compatibility: Supports a comprehensive range of traditional and A2L refrigerants including R410A

Lennox 99K63 Rollout Switch while the plastic cap isThe Lennox 99K63 Rollout Switch is a critical safety component designed for precise thermal monitoring in residential and commercial gas furnaces. Engineered as a manual reset rollout switch, this part is calibrated to actuate at 250 degrees F (+ 12F), immediately interrupting the burner circuit if it detects flame rollout or excessive heat concentrations outside the combustion chamber. This OEM Lennox replacement part, also identified by part number