Gas Furnace Ignitor & Flame Sensor Troubleshooting: Testing & Easy Fixes

If your gas furnace isn't heating or keeps going into "lockout" mode, the problem is often a faulty hot surface ignitor or a dirty flame sensor. In this HVAC repair guide, we show you how to diagnose, test, and replace these critical components to get your heat back on. In this video, you will learn: How to identify furnace lockout mode through diagnostic light codes [00:27]. The difference between Spark Igniters and Hot Surface Igniters [01:00]. How to test a hot surface ignitor using a multimeter (resistance/ohms check) [02:22]. Step-by-step removal and replacement of a cracked ceramic ignitor [03:13]. CRITICAL TIP: Why you should never touch the ceramic part of a new ignitor [04:19]. How a flame sensor works and how to clean it instead of replacing it [05:24]. Tools Needed: Multimeter Nut driver or Screwdriver Fine sandpaper or a damp rag (for cleaning the sensor) Safety First: Always shut off the power to your furnace before opening the burner compartment! #GasFurnaceRepair #FurnaceIgnitor #HVACMaintenance