🔥 Lennox Furnace Not Igniting? Fix It Fast with This Expert Guide

🔥 Lennox Furnace Not Igniting? Fix It Fast with This Expert Guide

📂 Category: Maintenance & Repair | 📅 2026-06-26 If your Lennox furnace runs the inducer motor but never fires up the burners, the most likely culprit is a dirty flame sensor — a 5-minute fix you can do yourself. If that doesn’t solve it, we’ll walk you through testing the ignitor, pressure switch, and gas valve safely, using the exact LED error code your control board is flashing. No heat doesn’t always mean an expensive service call. 🛑 What are the symptoms of the problem? You’ll typically notice a sequence like this when a Lennox furnace fails to ignite: The thermostat clicks on, and you hear the draft inducer motor start (a humming or whooshing sound). After 10–30 seconds, you may hear a single click or rapid clicking, but the burners never light — no flame, no glow. The furnace tries two or three more times, then locks out entirely, requiring a power reset to try again. The blower fan may still come on, pushing unheated air through the vents. A red LED on the control board blinks a…