The terminals are marked 'Herm' for the compressor lead

The red LED glows when the relay coil is energized and the contacts have successfully transferred (if the override is in Auto)

using an out-of-spec HVAC draft inducer switch can lead to dangerous venting conditions or frequent system lockouts

maintaining the factory safety rating of the HVAC system

Common Questions How do I verify if the Berko 4520-2048-000 is the correct limit switch for my heater

Rheem-Ruud 47-17359-30 Limit Switch The terminals are marked 'Herm'The Rheem Ruud 47 17359 30 Limit Switch is a critical safety component designed for high limit temperature monitoring in residential and commercial HVAC furnace systems. This OEM replacement part features a Single Pole Single Throw (SPST) normally closed configuration, engineered to interrupt the burner circuit when temperatures exceed safe operating parameters. With a fixed open temperature of 200F and a fixed close temperature of 180F, this red