Chimney Connection #10
Illustrated here is the connection of a contraflow refractory core, through its side channel, to a 230mm diameter terracotta flue tile.
The distance between the core and the flue tile is equal to that of two courses of brick i.e. the facing of the heater and the wall of the chimney, plus 1 inch for separation of the chimney from the heater, and flue tile from the chimney wall, and backfill between the core and facing.
Refractory brick are used to build a short transmission tunnel. The protruding tongue of brick at the top will protect the clay flue tile on the hot inner corner.
The tile is cut in a way that preserves its structural integrity as much as possible.
The flue tile is layed in place dry.
The second flue tile is layed in place dry. The opening that will give access to the side, and rear manifolds, and the chimney, is cut into this tile to avoid having to make 2 openings in the tile below.
In this situation the chimney will not be high so it is not a great concern, but the compressive force of the flue tiles above should not be under estimated.
View down the two dry stacked flue tiles. The connection to the transmission tunnel is at the top of the image and the access opening at the bottom.
The vertical faces of the transmission tunnel are gasketed with ceramic wool, before the flue tiles are finally layed.
The two flue tiles are layed in type N mortar. The cores of the tiles in the faces that were cut, have been grouted with concrete.