Lennox 34M73 Pressure Switch
The Lennox 34M73 Pressure Switch is a critical safety component designed for precise furnace draft inducer monitoring in residential and commercial heating systems. This OEM Lennox replacement part is factory-calibrated to a .22"wc set point, ensuring the exhaust vent maintains adequate negative pressure before allowing the ignition sequence to proceed. Featuring a Single Pole Single Throw (SPST) configuration and a standard 1/4" barb connection, this switch provides reliable circuit continuity for the integrated furnace control. As a direct crossover, the 34M73 is identical to 76777400 and replaces older legacy numbers such as 27K63 and 20516501. Constructed with a brass housing and stainless steel diaphragm, it is engineered to withstand the thermal stress and moisture common in high-efficiency condensing furnaces. Technicians should verify combustion air pressure and inspect for clogged condensate lines or port restrictions if a pressure switch error code persists on the HVAC control board.
Key Benefits for Technicians- Precise OEM Calibration: Pre-set to 0.22 inches Water Column (-0.22"wc) for exact compatibility with Lennox, Allied, and Armstrong equipment.
- Enhanced Durability: Features a stainless steel diaphragm and brass housing to resist corrosion in high-cycle environments.
- Simplified Retrofit: Standard 1/4" barb and SPST normally open contacts allow for fast, drop-in replacement on the draft inducer assembly.
- Universal Inducer Compatibility: Matches factory specifications for numerous 90% plus efficiency furnace models.
- How do I verify if the 34M73 is the correct replacement? Check the label on your existing switch for 0.22"wc or cross-reference the 34M73 and 76777400 part numbers in the manufacturer's parts manual.
- What causes a pressure switch stuck open error? Common culprits include a failing inducer motor, restricted venting pipes, a cracked heat exchanger, or moisture buildup in the pressure switch hose.
- Can I use a higher set point switch? No. Replacing a .22"wc switch with a higher rating will cause the furnace to fail to ignite, while a lower rating may bypass critical safety checks.
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: $51.22
-65%$51.22
$17.93Lennox 34M73 Pressure Switch
The Lennox 34M73 Pressure Switch is a critical safety component designed for precise furnace draft inducer monitoring in residential and commercial heating systems. This OEM Lennox replacement part is factory-calibrated to a .22"wc set point, ensuring the exhaust vent maintains adequate negative pressure before allowing the ignition sequence to proceed. Featuring a Single Pole Single Throw (SPST) configuration and a standard 1/4" barb connection, this switch provides reliable circuit continuity for the integrated furnace control. As a direct crossover, the 34M73 is identical to 76777400 and replaces older legacy numbers such as 27K63 and 20516501. Constructed with a brass housing and stainless steel diaphragm, it is engineered to withstand the thermal stress and moisture common in high-efficiency condensing furnaces. Technicians should verify combustion air pressure and inspect for clogged condensate lines or port restrictions if a pressure switch error code persists on the HVAC control board.
Key Benefits for Technicians- Precise OEM Calibration: Pre-set to 0.22 inches Water Column (-0.22"wc) for exact compatibility with Lennox, Allied, and Armstrong equipment.
- Enhanced Durability: Features a stainless steel diaphragm and brass housing to resist corrosion in high-cycle environments.
- Simplified Retrofit: Standard 1/4" barb and SPST normally open contacts allow for fast, drop-in replacement on the draft inducer assembly.
- Universal Inducer Compatibility: Matches factory specifications for numerous 90% plus efficiency furnace models.
- How do I verify if the 34M73 is the correct replacement? Check the label on your existing switch for 0.22"wc or cross-reference the 34M73 and 76777400 part numbers in the manufacturer's parts manual.
- What causes a pressure switch stuck open error? Common culprits include a failing inducer motor, restricted venting pipes, a cracked heat exchanger, or moisture buildup in the pressure switch hose.
- Can I use a higher set point switch? No. Replacing a .22"wc switch with a higher rating will cause the furnace to fail to ignite, while a lower rating may bypass critical safety checks.
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.
Product Information
Product Information
Shipping & Returns
Shipping & Returns
Description
The Lennox 34M73 Pressure Switch is a critical safety component designed for precise furnace draft inducer monitoring in residential and commercial heating systems. This OEM Lennox replacement part is factory-calibrated to a .22"wc set point, ensuring the exhaust vent maintains adequate negative pressure before allowing the ignition sequence to proceed. Featuring a Single Pole Single Throw (SPST) configuration and a standard 1/4" barb connection, this switch provides reliable circuit continuity for the integrated furnace control. As a direct crossover, the 34M73 is identical to 76777400 and replaces older legacy numbers such as 27K63 and 20516501. Constructed with a brass housing and stainless steel diaphragm, it is engineered to withstand the thermal stress and moisture common in high-efficiency condensing furnaces. Technicians should verify combustion air pressure and inspect for clogged condensate lines or port restrictions if a pressure switch error code persists on the HVAC control board.
Key Benefits for Technicians- Precise OEM Calibration: Pre-set to 0.22 inches Water Column (-0.22"wc) for exact compatibility with Lennox, Allied, and Armstrong equipment.
- Enhanced Durability: Features a stainless steel diaphragm and brass housing to resist corrosion in high-cycle environments.
- Simplified Retrofit: Standard 1/4" barb and SPST normally open contacts allow for fast, drop-in replacement on the draft inducer assembly.
- Universal Inducer Compatibility: Matches factory specifications for numerous 90% plus efficiency furnace models.
- How do I verify if the 34M73 is the correct replacement? Check the label on your existing switch for 0.22"wc or cross-reference the 34M73 and 76777400 part numbers in the manufacturer's parts manual.
- What causes a pressure switch stuck open error? Common culprits include a failing inducer motor, restricted venting pipes, a cracked heat exchanger, or moisture buildup in the pressure switch hose.
- Can I use a higher set point switch? No. Replacing a .22"wc switch with a higher rating will cause the furnace to fail to ignite, while a lower rating may bypass critical safety checks.
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.
