Page 4 / IM 685
Flue Box
The flue box is not installed at the factory because it would increase the width of the unit beyond the
allowable shipping width. All holes are prepunched and all required parts, including fasteners, are
furnished and shipped inside the burner vestibule of the unit. On Models 150 through 200, the flue box
and hardware is shipped in the same crate as the vestibule. Remove and discard the shipping cover
installed over the furnace tube outlets before installing the flue box.
1. Remove the screws
➁
in the casing of the unit that line up with the bottom lip holes of the flue box
tube sheet
➂
. These screws will later be replaced, at which time they will also attach the bottom of
the flue box to the unit.
2. Install the flue box tube sheet
➂
, attaching top to roof dam strip with screws
➀
. Do not attach
bottom at this time.
3. Apply a
1
⁄
8
to
3
⁄
16
inch bead of high temperature silicone around each tube to seal it to the flue box
tube sheet
➂
and prevent condensate from running back toward the unit along the outside of the
tube. See Figure 1. Also apply a bead of high temperature silicone to seal both sides to the bottom of
the flue box wrapper
√
, being careful not to obstruct the square drain holes in each front corner.
Three ounce tubes of silicone sealant are included in the envelope which also contains the electrical
schematics, etc. Models 020-100 are shipped with one tube and Models 110-200 are shipped with
two tubes.
4. Install flue box wrapper sheet
√
by sliding it up from below so as not to disturb the silicone seal
described in 3 above. Attach with side screws
➄
. At this time reinstall bottom screws
➁
.
Figure 1. Flue Box
Wind Deflector
The wind deflector is not installed at the factory because it would increase the width of the unit beyond
the allowable shipping width. The deflector is shipped in the burner vestibule of the unit. Install the
wind deflector over the combustion air intake opening of the burner compartment before operating the
burner. Use inner hinge screws on top hinged door (see Figure 2). Side hinged doors have holes for
mounting (see Figure 5). Models 020 and 025 have a different style wind deflector. It mounts on the
door and has a top opening flush with the roof of the unit (see Figure 14).
