ATAG Condensate Management / Flue Installation Issue

External flue terminal drips excessively or stains the wall

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

Incorrect flue angle causing condensate to run to terminal, Missing or blocked condensate drain from flue, Excessive condensation due to low return temperatures

How to Fix / Troubleshooting

Safety first: Flue work must comply with regulations; major changes require a qualified installer.

Visually inspect the flue terminal for correct orientation and any obvious damage.
Check that the condensate drain from the boiler is clear and properly connected.
Minor dripping in cold weather can be normal, but heavy staining or pooling indicates a flue slope or drain issue that should be corrected by an installer.

Repair Difficulty

Hard 4/5