Carrier HH19ZA940 Auto Limit Switch 85°F-140°F

The Carrier HH19ZA940 Auto Limit Switch which is designed to protect HVAC System equipment by turning it off if the surrounding temperature exceeds limits set 85°F to 140°F in this case. It has an element whose properties change with temperature, usually a bimetallic strip that bends or flexes with change in temperature. At the upper limit of temperature, say 140°F, the bimetallic strip bends and this action opens the switch to break the electrical connection to the equipment. This is not beneficial for the equipment as this causes overheating and is also dangerous to safety.