Lennox 79J73 Control Limit
Working with high-static environments or Lennox rooftop units requires a manual reset limit switch you can depend on. The Lennox 79J73 Control Limit is a critical safety component designed to monitor discharge air or internal heat exchanger temperatures. When temperatures exceed the calibrated threshold, this high temperature limit switch breaks the 24V control circuit, immediately shutting down the burners or heating elements to prevent catastrophic equipment damage or a cracked heat exchanger. Unlike auto-reset models, this 79J73 OEM replacement part forces a manual inspection, ensuring a technician identifies the root cause—be it a failed blower motor, obstructed ductwork, or a restricted air filter—before the system resumes operation.
This genuine Lennox HVAC part is engineered for a precise fit in Lennox LGB and LCB series units, among others. Its rugged construction withstands the high-cycling demands of commercial and residential heating platforms. As a professional, you know that using a secondary-market Lennox furnace limit switch can lead to nuisance tripping or, worse, failure to open during an over-temp event. Replacing a faulty or corroded limit with this original equipment ensures the system maintains its factory safety ratings and operational efficiency.
Key Benefits
- Critical Safety Protection: Instantly interrupts heating cycles if temperatures exceed safe operating limits, protecting the heat exchanger.
- Manual Reset Feature: Prevents "ghost" cycling by requiring a physical reset, ensuring technicians can diagnose airflow or mechanical failures.
- Direct OEM Compatibility: Designed specifically for Lennox HVAC systems, providing exact hole alignment and electrical terminal matching.
- Reliable Calibration: Precision-set internal bi-metal disc ensures consistent response times across the component's service life.
Common Questions
How do I know if my Lennox 79J73 limit switch has tripped?
If the furnace inducer runs but the ignition sequence fails to activate, or if your control board flashes a "Limit Switch Open" code, check the manual reset button on the 79J73. If it clicks when pressed, the switch was tripped due to an over-temperature condition.
Can I replace a 79J73 with a generic auto-reset switch?
No. Safety controls should always be replaced with the exact manufacturer specifications. Converting a manual reset limit to an automatic one can hide serious airflow issues, potentially leading to equipment failure or safety hazards.
What causes this limit switch to fail or trip frequently?
Frequent tripping is usually a symptom of restricted airflow. Check for a dirty evaporator coil, a failing blower capacitor, or closed supply registers. If the switch fails to continuity-test in the closed position while cool, the internal contacts are likely pitted or worn.
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.
Lennox 79J73 Control Limit
Working with high-static environments or Lennox rooftop units requires a manual reset limit switch you can depend on. The Lennox 79J73 Control Limit is a critical safety component designed to monitor discharge air or internal heat exchanger temperatures. When temperatures exceed the calibrated threshold, this high temperature limit switch breaks the 24V control circuit, immediately shutting down the burners or heating elements to prevent catastrophic equipment damage or a cracked heat exchanger. Unlike auto-reset models, this 79J73 OEM replacement part forces a manual inspection, ensuring a technician identifies the root cause—be it a failed blower motor, obstructed ductwork, or a restricted air filter—before the system resumes operation.
This genuine Lennox HVAC part is engineered for a precise fit in Lennox LGB and LCB series units, among others. Its rugged construction withstands the high-cycling demands of commercial and residential heating platforms. As a professional, you know that using a secondary-market Lennox furnace limit switch can lead to nuisance tripping or, worse, failure to open during an over-temp event. Replacing a faulty or corroded limit with this original equipment ensures the system maintains its factory safety ratings and operational efficiency.
Key Benefits
- Critical Safety Protection: Instantly interrupts heating cycles if temperatures exceed safe operating limits, protecting the heat exchanger.
- Manual Reset Feature: Prevents "ghost" cycling by requiring a physical reset, ensuring technicians can diagnose airflow or mechanical failures.
- Direct OEM Compatibility: Designed specifically for Lennox HVAC systems, providing exact hole alignment and electrical terminal matching.
- Reliable Calibration: Precision-set internal bi-metal disc ensures consistent response times across the component's service life.
Common Questions
How do I know if my Lennox 79J73 limit switch has tripped?
If the furnace inducer runs but the ignition sequence fails to activate, or if your control board flashes a "Limit Switch Open" code, check the manual reset button on the 79J73. If it clicks when pressed, the switch was tripped due to an over-temperature condition.
Can I replace a 79J73 with a generic auto-reset switch?
No. Safety controls should always be replaced with the exact manufacturer specifications. Converting a manual reset limit to an automatic one can hide serious airflow issues, potentially leading to equipment failure or safety hazards.
What causes this limit switch to fail or trip frequently?
Frequent tripping is usually a symptom of restricted airflow. Check for a dirty evaporator coil, a failing blower capacitor, or closed supply registers. If the switch fails to continuity-test in the closed position while cool, the internal contacts are likely pitted or worn.
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.
Product Information
Product Information
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Description
Working with high-static environments or Lennox rooftop units requires a manual reset limit switch you can depend on. The Lennox 79J73 Control Limit is a critical safety component designed to monitor discharge air or internal heat exchanger temperatures. When temperatures exceed the calibrated threshold, this high temperature limit switch breaks the 24V control circuit, immediately shutting down the burners or heating elements to prevent catastrophic equipment damage or a cracked heat exchanger. Unlike auto-reset models, this 79J73 OEM replacement part forces a manual inspection, ensuring a technician identifies the root cause—be it a failed blower motor, obstructed ductwork, or a restricted air filter—before the system resumes operation.
This genuine Lennox HVAC part is engineered for a precise fit in Lennox LGB and LCB series units, among others. Its rugged construction withstands the high-cycling demands of commercial and residential heating platforms. As a professional, you know that using a secondary-market Lennox furnace limit switch can lead to nuisance tripping or, worse, failure to open during an over-temp event. Replacing a faulty or corroded limit with this original equipment ensures the system maintains its factory safety ratings and operational efficiency.
Key Benefits
- Critical Safety Protection: Instantly interrupts heating cycles if temperatures exceed safe operating limits, protecting the heat exchanger.
- Manual Reset Feature: Prevents "ghost" cycling by requiring a physical reset, ensuring technicians can diagnose airflow or mechanical failures.
- Direct OEM Compatibility: Designed specifically for Lennox HVAC systems, providing exact hole alignment and electrical terminal matching.
- Reliable Calibration: Precision-set internal bi-metal disc ensures consistent response times across the component's service life.
Common Questions
How do I know if my Lennox 79J73 limit switch has tripped?
If the furnace inducer runs but the ignition sequence fails to activate, or if your control board flashes a "Limit Switch Open" code, check the manual reset button on the 79J73. If it clicks when pressed, the switch was tripped due to an over-temperature condition.
Can I replace a 79J73 with a generic auto-reset switch?
No. Safety controls should always be replaced with the exact manufacturer specifications. Converting a manual reset limit to an automatic one can hide serious airflow issues, potentially leading to equipment failure or safety hazards.
What causes this limit switch to fail or trip frequently?
Frequent tripping is usually a symptom of restricted airflow. Check for a dirty evaporator coil, a failing blower capacitor, or closed supply registers. If the switch fails to continuity-test in the closed position while cool, the internal contacts are likely pitted or worn.
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.
