OEM Lennox Gas Valve — 78L42
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The genuine OEM Lennox 78L42 gas valve meters and regulates the gas supply feeding your Lennox furnace burners. On each heating cycle it energizes to deliver a precisely regulated flow of fuel for clean, efficient combustion, then closes securely the moment the thermostat is satisfied or a safety circuit trips. Because it directly governs both fuel delivery and shutoff, this valve sits at the heart of your furnace's safe operation.
Common failure symptoms: no ignition or repeated ignition lockouts, a furnace that produces only cold air, an audible click with no corresponding gas flow, delayed or rough ignition, inconsistent flame size, or a valve that buzzes, sticks, or fails to seal completely when de-energized.
Why OEM matters: the Lennox 78L42 is calibrated to your system's exact manifold pressure and control voltage, ensuring correct BTU output and dependable safety shutoff. Generic replacements can misregulate gas pressure, trigger nuisance faults, and compromise combustion safety. Installing the factory-specified valve protects your equipment, maintains rated efficiency, and keeps your warranty intact.
Shipping Information
- Orders placed before 3PM CST ship same business day
- Standard delivery: 2-5 business days
- Express shipping available at checkout
- Free shipping on orders over $75
- Tracking number emailed upon shipment
Return Policy
- 30-day returns on unused parts in original packaging
- Electrical parts (capacitors, contactors, control boards) are final sale once installed
- Email info@nationalhvacparts.com to initiate a return
- Refunds processed within 5-7 business days