What does 14 mean?
Gas furnace failed to ignite after multiple attempts.
Common causes
- Failed hot surface igniter
- Dirty or faulty flame sensor
- Gas supply off or low pressure
- Failed gas valve
- Cracked igniter
Diagnostic & testing steps
- 1. Check gas supply valve is open
- 2. Inspect hot surface igniter for cracks - resistance should be 40-200 ohms
- 3. Clean flame sensor rod with fine steel wool
- 4. Test flame sensor: should read 2-6 microamps during flame
- 5. Verify gas pressure at manifold: 3.5 in WC for natural gas
Tools required
- Multimeter
- Microamp meter
- Manometer
OEM parts & part numbers
Hot Surface Igniter, Flame Sensor, Gas Valve
Part numbers: LH33ZS004, LH680013, EF32CW054
Safety warning
⚠️ GAS HAZARD: Do not bypass ignition safety controls. Ensure adequate ventilation when checking for gas leaks.
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