What are the secondary air tubes?

The replacement secondary air tubes are designed to slip over the burnt down tips of the existing air tubes which are welded into the back plate of the fire, these existing tubes need to be cut down to approx. 70mm long from the face of the rear ceramic or 100mm long from the steel back plate surface behind the ceramic, this should allow the replacement air tubes to slide in and over the short piece of tube left, we recommend applying a small amount of fire cement on the end of the original stump to seal and secure the new tubes on.  If the original air tubes are too long then these will need to be cut down to suit.