This is a normally closed (NC) switch that opens on temperature rise to break the circuit when the 220°F threshold is reached

the 71520318 is the official replacement for 71520304

For technicians working on unit heater venting

Lennox often uses these suffixes to denote packaging variations or revision cycles

requiring a filter-drier replacement to prevent system damage

Nordyne 104876703R Programmed Motor R-407C This is a normally closedThe Nordyne 104876703R Replacement Motor Program G7SA 072 B is a factory authorized replacement blower motor engineered for select Nordyne, Gibson, Frigidaire, Intertherm, Maytag, Tappan, and related furnace platforms utilizing the G7SA 072 B configuration. Designed to restore proper airflow performance and maintain furnace operating efficiency, this furnace blower motor provides an exact fit solution for HVAC service technicians and contractors