Lennox 75M20 Pressure Switch
The Lennox 75M20 Pressure Switch is a critical safety component engineered for high-altitude gas furnace applications, specifically calibrated for elevations between 4501 and 7500 feet. This OEM Lennox replacement part, also identified as 75M2001, monitors the inducer motor's static pressure to ensure the combustion air system is clear and operational before allowing the ignition sequence to initiate. With a precise fixed set point of 0.75" WC (water column), this SPST furnace pressure switch prevents hazardous operation caused by blocked vent pipes, failed draft inducers, or intake restrictions common in thinner high-altitude air. Designed for Lennox gas furnaces and rooftop units, the durable sheet metal housing and high-reliability contacts provide the consistent switching required for demanding commercial and residential HVACR environments. Reliable pressure sensing is essential for maintaining equipment uptime and verifying flue gas evacuation, making this high altitude pressure switch a standard inventory item for technicians servicing mountain-region installations.
Key Benefits- Altitude-Specific Calibration: Factory-set at 0.75" WC to ensure reliable HVAC system safety in high-elevation zones from 4501 to 7500 feet.
- Genuine OEM Compatibility: A direct replacement for Lennox 75M20 and 75M2001, ensuring exact fitment and terminal alignment for faster field installs.
- Enhanced Safety Logic: Precisely monitors draft inducer performance to prevent ignition during venting failures or air-flow obstructions.
- Rugged Industrial Build: Features a robust casing designed to withstand the thermal cycling and vibration typical of Lennox heating equipment.
What are the symptoms of a failing Lennox 75M20 pressure switch?
Common signs include the furnace failing to ignite despite the inducer motor running, or diagnostic flash codes indicating a "pressure switch stuck open" or "pressure switch remains closed" fault. Technicians should use a manometer to verify the 0.75" WC set point during troubleshooting.
Can I use this switch at sea level?
No. This switch is specifically calibrated for 4501-7500ft high altitude. Using a high-altitude switch in lower elevations can cause the furnace to run in unsafe conditions or cause frequent nuisance trips because the air density and pressure requirements differ significantly.
Is this an SPST or DPST configuration?
The 75M20 is a Single Pole Single Throw (SPST) switch designed to close when the inducer motor creates the required negative pressure, completing the 24V safety circuit to the ignition control board.
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.
Original: $83.82
-65%$83.82
$29.34Product Information
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Description
The Lennox 75M20 Pressure Switch is a critical safety component engineered for high-altitude gas furnace applications, specifically calibrated for elevations between 4501 and 7500 feet. This OEM Lennox replacement part, also identified as 75M2001, monitors the inducer motor's static pressure to ensure the combustion air system is clear and operational before allowing the ignition sequence to initiate. With a precise fixed set point of 0.75" WC (water column), this SPST furnace pressure switch prevents hazardous operation caused by blocked vent pipes, failed draft inducers, or intake restrictions common in thinner high-altitude air. Designed for Lennox gas furnaces and rooftop units, the durable sheet metal housing and high-reliability contacts provide the consistent switching required for demanding commercial and residential HVACR environments. Reliable pressure sensing is essential for maintaining equipment uptime and verifying flue gas evacuation, making this high altitude pressure switch a standard inventory item for technicians servicing mountain-region installations.
Key Benefits- Altitude-Specific Calibration: Factory-set at 0.75" WC to ensure reliable HVAC system safety in high-elevation zones from 4501 to 7500 feet.
- Genuine OEM Compatibility: A direct replacement for Lennox 75M20 and 75M2001, ensuring exact fitment and terminal alignment for faster field installs.
- Enhanced Safety Logic: Precisely monitors draft inducer performance to prevent ignition during venting failures or air-flow obstructions.
- Rugged Industrial Build: Features a robust casing designed to withstand the thermal cycling and vibration typical of Lennox heating equipment.
What are the symptoms of a failing Lennox 75M20 pressure switch?
Common signs include the furnace failing to ignite despite the inducer motor running, or diagnostic flash codes indicating a "pressure switch stuck open" or "pressure switch remains closed" fault. Technicians should use a manometer to verify the 0.75" WC set point during troubleshooting.
Can I use this switch at sea level?
No. This switch is specifically calibrated for 4501-7500ft high altitude. Using a high-altitude switch in lower elevations can cause the furnace to run in unsafe conditions or cause frequent nuisance trips because the air density and pressure requirements differ significantly.
Is this an SPST or DPST configuration?
The 75M20 is a Single Pole Single Throw (SPST) switch designed to close when the inducer motor creates the required negative pressure, completing the 24V safety circuit to the ignition control board.
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.
