Downdraft in Flues

In some installations it is possible to experience downdraft in a flue system.

This can result in small quantities of smoke being expelled from the boiler, typically through the air intakes.

The problem will tend to occur when the boiler is in an initial firing sequence, where fuel is lit, however the flue has not warmed up enough to create enough pull. 

The downdraft itself is caused by wind hitting the chimney in a downhill direction, and as such is usually only experienced where the flue is located near taller buildings or trees. As the wind passes over the taller building it will follow the contour of the ground (or buildings and trees) and drop.

To solve the problem an anti-down-draft cowl is recommended.

These are available from Specflue sales on 0800 9020220.

View our cowl catalogue here.