When should I replace these rubber parts

As a direct furnace pressure switch replacement

Precise Thermal Response: Opens at a strictly calibrated 290°F to prevent cabinet damage and ensure fire safety

specialized orifice wrenches

Rheem-Ruud 47-21711-11 Limit Switch When should I replace theseThe Rheem Ruud 47 21711 11 Limit Switch is a critical safety component designed for precise thermal regulation in HVAC furnace systems. As a genuine OEM replacement part, this normally closed (SPST) switch is engineered to disrupt the burner circuit if internal plenum temperatures exceed safety thresholds. It features a fixed open temperature of 180F and a fixed close temperature of 160F, providing a 20F differential that prevents rapid cycling of the