Reznor 193809 Pressure Switch

The Reznor 193809 Pressure Switch is a mission-critical 0.65" WC air pressure switch kit designed for precise combustion air monitoring in Reznor unit heaters. Calibrated to trigger at a 0.65-inch water column setpoint, this HVAC induction fan safety switch ensures the inducer motor maintains the necessary vacuum pressure for safe flue gas venting before ignition. This replacement kit is the correct Reznor OEM part cross-reference for legacy pressure switches, specifically addressing standard elevation applications where maintaining the integrity of the combustion air safety circuit is required for continuous operation.

Built for high-cycle reliability in commercial environments, this Honeywell or FS series replacement features a rugged housing and updated terminal configurations to meet modern ANSI/CSA safety standards. The kit includes the necessary 1/4" and 3/16" quick-connect terminals and silicone tubing to accommodate variations in older cabinet designs across (H)SC, SCA, and UDAP series. When diagnosing furnace pressure switch failure, such as short cycling or inducer-only run cycles, the 193809 offers a direct-fit solution for maintaining factory-specified safety parameters without unnecessary field modifications.

• Precise 0.65" WC Setpoint: Pre-calibrated for exact differential pressure monitoring to prevent ignition during improper venting.
• Comprehensive Kit Components: Includes updated wiring terminals and high-temp silicone tubing for seamless integration into older inducer assemblies.
• OEM-Grade Construction: Designed to withstand the thermal stress of heavy commercial heating cycles without drift in the pressure setpoint.
• Enhanced Equipment Safety: Prevents gas valve activation if the flue is obstructed or the inducer fan falls below required RPM.

What are the symptoms of a bad Reznor pressure switch?
Technicians typically observe the inducer motor running but the ignition sequence failing to engage, or the system throwing an "airflow" or "open pressure switch" error code on the control board.

Can this switch be used for high-altitude applications?
This 0.65" WC switch is generally for standard elevations (0–4000 feet). For installations above this range, consult the unit's technical manual as a different pressure setpoint (such as 0.40" WC or 0.50" WC) is typically required to account for lower air density.

Are the terminals compatible with older wiring harnesses?
Yes. Because Reznor updated terminal sizes to meet ANSI requirements in 1999, this kit provides assorted quick-connect terminals to ensure compatibility regardless of the unit's manufacture date.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.