BoilerTroubleshooting2026-02-26
Boiler Flame Keeps Going Out
A flame that won't stay lit points to the flame sensor, gas supply or condensate.
If your boiler's flame keeps extinguishing, the flame-proving system is the place to look.
Common causes
A dirty flame sensor, low or interrupted gas supply, or a blocked condensate pipe cause the flame to drop out.
What to do
Check that other gas appliances work and the condensate isn't frozen; the flame sensor or gas valve needs a technician.
Key takeaways
- Dirty flame sensor is common
- Check gas supply and condensate
- Don't keep resetting
- Needs a technician to confirm
Need help with your boiler?
Licensed, gas-certified technicians serving Greater Vancouver since 1999. CombiBoiler.ca — A division of ROMA Heating Ltd..
Frequently asked questions
More Boiler articles
Boiler Leaking Water: Causes and RepairsBoiler leaks usually come from the pressure-relief valve, pump seals, fittings or the heat exchanger.Boiler No Heat: Emergency TroubleshootingNo heat from a boiler is often pressure, ignition, a pump or a tripped lockout — here's how to check.Why Your Boiler Keeps Losing PressureRecurring pressure loss usually means a leak, a failed relief valve, or a waterlogged expansion vessel.Boiler No Hot Water: Common CausesHeating works but taps run cold? Suspect the diverter valve, flow sensor or plate heat exchanger.Boiler Kettling and Banging Noises ExplainedThat rumbling 'kettle' sound usually means limescale or sludge in the heat exchanger.Combi vs Conventional Boiler: Which Is Best?Combi boilers save space and give on-demand hot water; conventional systems suit high simultaneous demand.
More from our knowledge base
Furnace Won't Turn On? Causes and FixesFurnaceFurnace Blowing Cold Air: What to CheckFurnaceWhy Your Furnace Short-Cycles (and How to Stop It)FurnaceNo Heat? Emergency Furnace Repair GuideFurnaceFurnace Making Strange Noises: A Sound-by-Sound GuideFurnaceAnnual Furnace Maintenance ChecklistFurnaceAll ArticlesBrowse the full library