Mars L170-4 Limit Switch, Open on Temp Rise at 170, Auto Close at 130 (39021)

About the Mars L170-4 Limit Switch, Open on Temp Rise at 170, Auto Close at 130 (39021)

Save when you get the Mars 39021 170 Limit Switch L170-40 Auto Reset 3/4" here at PlumbersStock.com. Limit switches are sensors that detect when a furnace has exceeded operational temperature limits and shut the appliance down as a safety measure. The way it works is that if your temperature gets to a concerning level, the limit switch will automatically open the circuit so it shuts off. It will remain off until the switch automatically closes the circuit when the temperature reaches the off threshold. Mars is a trusted HVAC brand known for quality manufacturing.