or an audible humming sound from the outdoor unit without ignition

and AF-3 airflow switch series

ensures the manifold pressure is properly regulated for propane’s higher BTU content

Simplified Wiring: Replaces spade terminals for a cleaner

this auxiliary interlock switch delivers the mechanical precision required by veteran technicians and electrical contractors

York S1-025-29041-001 Limit Switch or an audible humming soundThe York S1 025 29041 001 Limit Switch is a critical OEM safety component engineered for precise thermal monitoring in high efficiency furnace and air handling units. Specifically designed as an Auto Reset Limit Switch, it features a 3 inch probe insertion to accurately gauge plenum temperatures. This HVAC high limit control is calibrated to trigger at a high end threshold of 220F and reset at 190F, preventing heat exchanger damage and ensuring safe