BoilerTroubleshooting2026-02-26
Boiler Banging on Startup
A bang on ignition often means delayed ignition — a safety item worth servicing.
A loud bang when your boiler lights points to delayed ignition or trapped air.
Common causes
Delayed ignition from dirty burners (gas builds up then ignites with a bang) or trapped air and sludge can cause startup banging.
What to do
Delayed ignition is a safety concern needing prompt service; bleeding and flushing address air and sludge.
Key takeaways
- Bang on ignition = delayed ignition
- A safety item — service promptly
- Air and sludge can also bang
- Don't ignore it
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