Reznor 205821 Pressure Switch

The Reznor 205821 Pressure Switch is a critical safety component designed for precise combustion air verification in high-efficiency unit heaters and duct furnaces. This OEM Reznor replacement part is factory-calibrated to a .50"wc set point, ensuring the inducer motor generates the necessary draft before the ignition sequence initiates. Featuring a single-pole single-throw (SPST) contact configuration, the switch closes upon sensing sufficient pressure, protecting the heat exchanger from improper venting or airflow restrictions. It includes a standard 1/4" barb connection for secure attachment to silicone sensing tubing and is built to withstand operating temperatures from -40°F to 150°F. For technicians troubleshooting intermittent ignition or lockout codes, installing this HVAC pressure switch ensures the system maintains its factory-specified operating parameters. Using authentic Reznor combustion air switches is essential for fleet maintenance and long-term equipment reliability in commercial or industrial applications.

• Precise .50"wc Calibration: Engineered to match exact Reznor HVAC equipment specifications for reliable safety circuit closure.
• OEM Compatibility: Replaces part numbers IS20232-5272 and 149879, ensuring a direct fit without modifying mounting brackets.
• Durable Construction: High-grade materials resist corrosion and handle the demanding duty cycles of industrial unit heaters.
• Standardized Connections: The 1/4" barb connection simplifies field replacement and ensures a leak-free seal with existing pneumatic lines.

What are the symptoms of a failing Reznor 205821 switch?
A faulty switch typically causes the inducer to run continuously without the igniter glowing, often resulting in a specific lockout code on the integrated control board. Technicians should check for cracked tubing or pressure switch diaphragm failure if the furnace fails to fire.

Can this switch be used in positive and negative pressure systems?
Yes, the 205821 is designed for versatility in various Reznor models, including RP, RPB, and SC series, managing both positive and negative pressure environments up to 100 psi.

Is this a direct replacement for plastic or metal switches?
This black plastic switch (PN 205821) is the standard replacement for most modern units. If you are replacing an older obsolete metal switch, additional mounting hardware or a conversion kit may be required depending on the heater's manufacture date.

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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.