Boiler flue terminal shows signs of staining, dripping, or plume appears abnormal, but boiler continues to run.
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Flue issues can lead to unsafe operation. If you suspect flue gas re-entry into the property, switch off the boiler and ventilate the area.
User-level checks:
- Visually inspect the outside flue terminal for damage or obstruction.
- Do not attempt to dismantle the flue yourself.
Technical checks (qualified personnel):
- Inspect the full flue run for correct gradient (towards the boiler or terminal as specified) and secure fixings.
- Check all flue joints for signs of leakage or staining; remake or replace sections as necessary.
- Ensure condensate drainage from the flue is correct and not pooling.
- Perform flue gas analysis to confirm safe combustion and no recirculation.
Any flue modifications must comply with Chaffoteaux instructions and local regulations.