Specifications
Installation
built-in inStallation:
Installation without a masonry replace -
The M55C-FPI can be installed without an existing masonry replace by building an enclosure for the 
unit to be installed in. This enclosure must be a minimum of 18” deep, 36” wide and 23-1/4” high and 
made with ½” noncombustible cement board. The oor of the enclosure must consist of a minimum of 
1-1/4” air space and a layer of ½” noncombustible cement board and a layer of tile. The air space must 
be supported with sheet metal studs and have no combustible material in the air space. All venting for 
Built-In installation must use PL or L venting and be installed with vent manufacturer’s recommended 
clearances. Refer to page 9 for Clearances to Combustibles.
36"
1
1
4
"
48"
37"
16"
26"
18"
11
1
2
"
9
5
8
"
18"
23 1/4"
5
1
8
"
4
7
8
"
11
5
8
"
C
L
2X4 Steel studs 
minimum 1-1/4" thick 
Wood Trim
Cement board
box and facing
Cement board 
screwed to steel studs
Wood Framing
Wall
Thimble
Tile over cement
 board
Optional fresh 
air intake
14
Figure 11: Built-In Specifications










