the internal junction has likely degraded

ensuring the orifice diameter remains constant over time

this high limit sensor features a standard L300 degree setting with a manual reset function

double-throw (DPDT) configuration depending on specific board integration

Direct Replacement: Specifically designed to replace the 21D64-1 and common carbide units without requiring complex control board modifications

Trane RLY1172 Fan Relay Els PW 17895 the internal junction has likelyThe Trane RLY1172 is a high performance SP4T fan relay designed for precise fan motor control in commercial and residential HVAC systems. Built to handle 230V line voltage at a 16A FLA (Full Load Amperage) rating, this heavy duty relay is activated by a standard 24V coil. The single pole, four throw configuration allows for versatile circuit switching, making it a critical component for managing multiple fan speeds or auxiliary equipment in air