BoilerTroubleshooting2026-01-28
Boiler Ignition Failure Explained
Repeated clicking with no ignition usually means the igniter, flame sensor, gas valve or condensate.
When a boiler clicks but won't light, or fires then locks out, the ignition system is the place to look.
Common causes
A faulty igniter or flame sensor, a gas-supply issue, low pressure, or a blocked condensate pipe (which trips a safety lockout) are the usual reasons for ignition failure.
What not to do
Avoid repeatedly resetting a boiler after several lockouts — it can flood the combustion chamber with gas. Get it diagnosed instead.
Key takeaways
- Don't keep resetting after repeated lockouts
- Check pressure and for condensate blockage
- A frozen condensate pipe is common in cold snaps
- Igniter/flame-sensor faults need a technician
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