Retrofitting a Pisla HTT 602 door

Existing door is 18" wide and 19" high. Firebox is 22" wide. Pisla HTT 602 door is 22" wide and 16" high (550mm x 410mm) Pisla catalogue Old door is removed by unscrewing tapcons. Brick door jambs were protected with firebrick splits fastened with silicone on the outside edge and fire cement on the inside edge. This brick shows a through-hole for the tapcons, which grab the facing bricks. The splits were loose because the silicone had burned out. It is Type 1 GE clear, which we have tested to 500F continuous, and 600F intermittent. View of the brick door jamb. On the left (outside) edge, you can clearly see the crystallized silicone. Fire cement is on the inside edge. The top door jamb split was in a slightly protected location, and the silicone survived. To the left, you can see firebrick split heat shield bricks that protect the steel firebox lintel and the steel facing lintel. The terracotta plaster grounds are wide enough to accomodate the new door. However, the facing bricks need to be cut back 1". A Bosch SDS drill/hammer and a 3/8 drill bit make quick work of the demo. The drill bit goes in, and then the hammering action splits the cored brick easily. (Not shown) a large shopvac with HEPA filter is running to catch any dust. 1/2" thick ceramic fiber is folded as shown. It is used to fill the gap between the heat shield bricks and the facing lintel. The heat shield bricks are pushed forward enough to touch the back of the new door frame.  The 1"  facing brick strip visible will provide support for a new piece of terracotta that is needed to fill the gap down to the heat shield bricks. This is because the old door had a large flange at the top, and was taller. The bond between the new terracotta and old facing bricks is critical, and will be done with silicone. The heat shield bricks plus the ceramic fiber ensure that the silicone joint will stay below 500F. Door jamb brick knocked back. New terracotta strip in place. The Pisla door comes with a gasket groove on the rear face of the flange. We glued in 3/8" fiberglass rope. This will provide the seal, rather than stuffing ceramic fiber between the door jamb and the return flange. Door is tapconned into place. The door jamb is repaired with castable refractory, in the white bucket. Rebuilt door jamb in use. Bricks to reconfigure the air supply at the front of the firebox. Ready to light. Beautiful 22" fire view. Click for video of fire view. Update: February 14, 2022:              One of our clients did this retrofit on his heater and sent us this nice report: Update: November 24, 2015: Austrian Eco-labelled firebox retrofit

This page last updated on February 14, 2022
This page was created on January 8, 2014