Lennox 21J99 Control Board
The Lennox 21J99 is a genuine OEM replacement for aging or failed Direct Spark Ignition (DSI) control boards in residential furnace applications. Labeled under catalog number 21J99 and part number 105802-02, this module manages the trial-for-ignition period and flame sensing and operation of the inducer motor to ensure stable combustion cycles. Designed specifically for Lennox-branded equipment, it replaces outdated ignition modules that cause common service issues like intermittent lockout or failure to sense flame. As a veteran-grade component, it integrates seamlessly with existing harnesses, maintaining the factory-specified timing for spark duration and gas valve energization. This furnace circuit board is essential for restoring the safety protocols of the heating system, providing the reliable Direct Spark Ignition sequences required for high-efficiency operation without the need for field modifications or universal adapter kits.
Key Benefits for Technicians:
- Exact OEM Specifications: Matches the factory Lennox 21J99 logic, ensuring the DSI control board maintains correct inducer pre-purge and post-purge timings.
- Simplified Troubleshooting: Features standard diagnostic layouts to help identify Lennox furnace ignition problems such as failed flame rectification or pressure switch faults.
- Broad Compatibility: A drop-in fit for numerous Lennox furnace models, eliminating the variability found in generic furnace control board replacement parts.
- Optimized Ignition: Provides a high-energy spark to the electrode for consistent Direct Spark Ignition (DSI), even in cold environments.
Common Technical Questions:
Can I use this board if my furnace uses a standing pilot?
No, this component is specifically engineered for Direct Spark Ignition (DSI) systems. It will not function with standing pilot or hot surface ignition (HSI) furnaces.
What does it mean if the LED on the Lennox 21J99 is flashing?
The onboard diagnostics use flash codes to signal specific faults like a high-limit trip, pressure switch failure, or flame rollout. Check the service panel on your unit for the specific code definitions associated with Lennox HVAC parts.
Is this a universal ignition module?
While it fits many models, this is a dedicated Lennox OEM control board. It is designed to match the specific voltage requirements and pin configurations of Lennox equipment to ensure reliable system communication.
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: $125.68
-65%$125.68
$43.99Lennox 21J99 Control Board
The Lennox 21J99 is a genuine OEM replacement for aging or failed Direct Spark Ignition (DSI) control boards in residential furnace applications. Labeled under catalog number 21J99 and part number 105802-02, this module manages the trial-for-ignition period and flame sensing and operation of the inducer motor to ensure stable combustion cycles. Designed specifically for Lennox-branded equipment, it replaces outdated ignition modules that cause common service issues like intermittent lockout or failure to sense flame. As a veteran-grade component, it integrates seamlessly with existing harnesses, maintaining the factory-specified timing for spark duration and gas valve energization. This furnace circuit board is essential for restoring the safety protocols of the heating system, providing the reliable Direct Spark Ignition sequences required for high-efficiency operation without the need for field modifications or universal adapter kits.
Key Benefits for Technicians:
- Exact OEM Specifications: Matches the factory Lennox 21J99 logic, ensuring the DSI control board maintains correct inducer pre-purge and post-purge timings.
- Simplified Troubleshooting: Features standard diagnostic layouts to help identify Lennox furnace ignition problems such as failed flame rectification or pressure switch faults.
- Broad Compatibility: A drop-in fit for numerous Lennox furnace models, eliminating the variability found in generic furnace control board replacement parts.
- Optimized Ignition: Provides a high-energy spark to the electrode for consistent Direct Spark Ignition (DSI), even in cold environments.
Common Technical Questions:
Can I use this board if my furnace uses a standing pilot?
No, this component is specifically engineered for Direct Spark Ignition (DSI) systems. It will not function with standing pilot or hot surface ignition (HSI) furnaces.
What does it mean if the LED on the Lennox 21J99 is flashing?
The onboard diagnostics use flash codes to signal specific faults like a high-limit trip, pressure switch failure, or flame rollout. Check the service panel on your unit for the specific code definitions associated with Lennox HVAC parts.
Is this a universal ignition module?
While it fits many models, this is a dedicated Lennox OEM control board. It is designed to match the specific voltage requirements and pin configurations of Lennox equipment to ensure reliable system communication.
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 21J99 is a genuine OEM replacement for aging or failed Direct Spark Ignition (DSI) control boards in residential furnace applications. Labeled under catalog number 21J99 and part number 105802-02, this module manages the trial-for-ignition period and flame sensing and operation of the inducer motor to ensure stable combustion cycles. Designed specifically for Lennox-branded equipment, it replaces outdated ignition modules that cause common service issues like intermittent lockout or failure to sense flame. As a veteran-grade component, it integrates seamlessly with existing harnesses, maintaining the factory-specified timing for spark duration and gas valve energization. This furnace circuit board is essential for restoring the safety protocols of the heating system, providing the reliable Direct Spark Ignition sequences required for high-efficiency operation without the need for field modifications or universal adapter kits.
Key Benefits for Technicians:
- Exact OEM Specifications: Matches the factory Lennox 21J99 logic, ensuring the DSI control board maintains correct inducer pre-purge and post-purge timings.
- Simplified Troubleshooting: Features standard diagnostic layouts to help identify Lennox furnace ignition problems such as failed flame rectification or pressure switch faults.
- Broad Compatibility: A drop-in fit for numerous Lennox furnace models, eliminating the variability found in generic furnace control board replacement parts.
- Optimized Ignition: Provides a high-energy spark to the electrode for consistent Direct Spark Ignition (DSI), even in cold environments.
Common Technical Questions:
Can I use this board if my furnace uses a standing pilot?
No, this component is specifically engineered for Direct Spark Ignition (DSI) systems. It will not function with standing pilot or hot surface ignition (HSI) furnaces.
What does it mean if the LED on the Lennox 21J99 is flashing?
The onboard diagnostics use flash codes to signal specific faults like a high-limit trip, pressure switch failure, or flame rollout. Check the service panel on your unit for the specific code definitions associated with Lennox HVAC parts.
Is this a universal ignition module?
While it fits many models, this is a dedicated Lennox OEM control board. It is designed to match the specific voltage requirements and pin configurations of Lennox equipment to ensure reliable system communication.
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.
