Lennox 38M77 Pressure Switch
The Lennox 38M77 High Pressure Switch is a critical OEM safety component designed for R-410A HVAC systems. Engineered to monitor discharge line pressure, this switch prevents compressor damage by interrupting the control circuit when pressures exceed safe operating limits. With a factory-calibrated trip setting of 640 psi and a reset threshold of 475 psi, it ensures precise high-limit protection in commercial and industrial rooftop units and split systems. This OEM Lennox replacement part, also identified by part number 38M7701, is the standard choice for maintaining system integrity in Lennox model series KHA, LCA, and TPA.
For service technicians, the 640-475# pressure switch offers a robust sensing mechanism that withstands the rapid cycling and harsh vibrations typical of high-tonnage condensers. Integrating a genuine Lennox 38M77 ensures compatibility with existing wiring harnesses and mounting brackets, eliminating the need for field modifications. Whether you are troubleshooting a high pressure trip or performing preventative maintenance, using this HVAC pressure switch ensures your equipment operates within its engineered thermal and pressure parameters, protecting the longevity of the compressor.
Key Benefits- Precise Pressure Regulation: Features a high-limit 640 psi cutout and a 475 psi cut-in to prevent catastrophic system failure.
- Broad Compatibility: Directly replaces Lennox 38M7701 and fits a wide range of Allied, Armstrong, and Ducane commercial equipment.
- R-410A Optimized: Specifically rated for the higher operating pressures of R-410A refrigerant cycles.
- Durable Construction: Built with industrial-grade materials to resist corrosion and electrical fatigue in outdoor environments.
What causes a Lennox 38M77 to trip?
Common triggers include a dirty condenser coil, a failed condenser fan motor, or non-condensables in the refrigerant circuit causing high head pressure.
Is this a manual or automatic reset switch?
This specific model is an automatic reset switch, meaning it will close the circuit once the system pressure drops back down to the 475 psi threshold.
Can I use this on a system with R-22 refrigerant?
No, the 640/475 psi set points are calibrated for R-410A. Using this on R-22 equipment could lead to dangerously high pressures before the switch trips.
This item is not eligible for free shipping.
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: $25.37
-65%$25.37
$8.88Lennox 38M77 Pressure Switch
The Lennox 38M77 High Pressure Switch is a critical OEM safety component designed for R-410A HVAC systems. Engineered to monitor discharge line pressure, this switch prevents compressor damage by interrupting the control circuit when pressures exceed safe operating limits. With a factory-calibrated trip setting of 640 psi and a reset threshold of 475 psi, it ensures precise high-limit protection in commercial and industrial rooftop units and split systems. This OEM Lennox replacement part, also identified by part number 38M7701, is the standard choice for maintaining system integrity in Lennox model series KHA, LCA, and TPA.
For service technicians, the 640-475# pressure switch offers a robust sensing mechanism that withstands the rapid cycling and harsh vibrations typical of high-tonnage condensers. Integrating a genuine Lennox 38M77 ensures compatibility with existing wiring harnesses and mounting brackets, eliminating the need for field modifications. Whether you are troubleshooting a high pressure trip or performing preventative maintenance, using this HVAC pressure switch ensures your equipment operates within its engineered thermal and pressure parameters, protecting the longevity of the compressor.
Key Benefits- Precise Pressure Regulation: Features a high-limit 640 psi cutout and a 475 psi cut-in to prevent catastrophic system failure.
- Broad Compatibility: Directly replaces Lennox 38M7701 and fits a wide range of Allied, Armstrong, and Ducane commercial equipment.
- R-410A Optimized: Specifically rated for the higher operating pressures of R-410A refrigerant cycles.
- Durable Construction: Built with industrial-grade materials to resist corrosion and electrical fatigue in outdoor environments.
What causes a Lennox 38M77 to trip?
Common triggers include a dirty condenser coil, a failed condenser fan motor, or non-condensables in the refrigerant circuit causing high head pressure.
Is this a manual or automatic reset switch?
This specific model is an automatic reset switch, meaning it will close the circuit once the system pressure drops back down to the 475 psi threshold.
Can I use this on a system with R-22 refrigerant?
No, the 640/475 psi set points are calibrated for R-410A. Using this on R-22 equipment could lead to dangerously high pressures before the switch trips.
This item is not eligible for free shipping.
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.
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Description
The Lennox 38M77 High Pressure Switch is a critical OEM safety component designed for R-410A HVAC systems. Engineered to monitor discharge line pressure, this switch prevents compressor damage by interrupting the control circuit when pressures exceed safe operating limits. With a factory-calibrated trip setting of 640 psi and a reset threshold of 475 psi, it ensures precise high-limit protection in commercial and industrial rooftop units and split systems. This OEM Lennox replacement part, also identified by part number 38M7701, is the standard choice for maintaining system integrity in Lennox model series KHA, LCA, and TPA.
For service technicians, the 640-475# pressure switch offers a robust sensing mechanism that withstands the rapid cycling and harsh vibrations typical of high-tonnage condensers. Integrating a genuine Lennox 38M77 ensures compatibility with existing wiring harnesses and mounting brackets, eliminating the need for field modifications. Whether you are troubleshooting a high pressure trip or performing preventative maintenance, using this HVAC pressure switch ensures your equipment operates within its engineered thermal and pressure parameters, protecting the longevity of the compressor.
Key Benefits- Precise Pressure Regulation: Features a high-limit 640 psi cutout and a 475 psi cut-in to prevent catastrophic system failure.
- Broad Compatibility: Directly replaces Lennox 38M7701 and fits a wide range of Allied, Armstrong, and Ducane commercial equipment.
- R-410A Optimized: Specifically rated for the higher operating pressures of R-410A refrigerant cycles.
- Durable Construction: Built with industrial-grade materials to resist corrosion and electrical fatigue in outdoor environments.
What causes a Lennox 38M77 to trip?
Common triggers include a dirty condenser coil, a failed condenser fan motor, or non-condensables in the refrigerant circuit causing high head pressure.
Is this a manual or automatic reset switch?
This specific model is an automatic reset switch, meaning it will close the circuit once the system pressure drops back down to the 475 psi threshold.
Can I use this on a system with R-22 refrigerant?
No, the 640/475 psi set points are calibrated for R-410A. Using this on R-22 equipment could lead to dangerously high pressures before the switch trips.
This item is not eligible for free shipping.
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.
