12
• If the roof jack crown is covered or blocked with snow, the
furnace will not operate properly. If the home is located
in regions where snow accumulation exceeds 7” (HUD
snowload zones) use an external roof jack extension
(p/n 901937). A maximum of 2 extensions per roof jacks
can be used. Extensions are optional accessories and
may be purchased through your distributor.
Locating & Cutting Roof / Ceiling Openings
IMPORTANT NOTE:
Do not allow debris to fall into the furnace. This
could cause unsafe operation and void the furnace
warranty. Use the top cap that comes with the furnace
packaging (or alternate protector) to prevent debris
from falling into the furnace before the final roof jack
connection is made.
NOTE: Refer to the installation instructions provided
with optional air conditioning packages when installing
furnaces with optional cooling coil cabinet or with optional
C* series indoor coils.
1. Locate center of Roof Jack opening, measure 13 1/2”
from the rear wall of closet or alcove along the center
line of furnace and floor opening. See Figure 19.
2. Cut ceiling and roof holes:
• Ceiling = 8 3/4” (222 mm) diameter
• Roof = 9 3/8” (238 mm) diameter
Installing The Roof Jack
1. Apply caulking compound on underside of roof flashing
to form a continuous strip at least 3/8” wide around the
underside of the perimeter of the flashing. For flat roof,
see Figure 20 or see Figure 21 if roof is pitched.
2. Connect roof jack assembly to the furnace. Insert
telescoping roof jack assembly through the opening
cut on the roof.
3. Connect inner flue pipe to vent collar of the furnace.
See Figure 22.
4. Connect combustion air pipe to furnace collar with sheet
metal screw. See Figure 22.
NOTES:
• It is recommended that the connection of the combustion
air pipe to the furnace be made before the flashing is
secured to the roof to maintain alignment of roof jack
and furnace connections.
• For replacement furnaces, be sure the inner flue pipe
connects over the furnace vent collar. DO NOT use a
smaller diameter inner flue pipe which could slide
inside the furnace vent collar and restrict the flow
of furnace flue products.
5. Attach roof flashing. If necessary, shift roof flashing
slightly in the roof opening so that assembly is in
alignment with furnace.
NOTE: If flashing is mounted on 12 degree angle, it
may be necessary to adjust the angle to match the roof
pitch; (1/12 - 4/12 maximum).
6. Press down firmly on roof flashing (over caulking) to
make the seal with roof water tight.
7. Secure flashing with appropriate fasteners. NOTE:
For added protection against leaks, coat the exposed
flashing plate and fasteners with approved roofing
compound.
Figure 20. Flat Roof
Secure roof jack with
appropriate fasteners
after connecting to
furnace
Caulk under roof
flashing to prevent
water leakage
Roof
Ceiling
Optional 2-piece ceiling
ring #902521
Upper Roof Jack Section
Secure lower roof
jack section with
no. 10 S.M. screws
Caulk under roof
ashing to prevent
water leakage
Optional Slant
Deck Flashing
Secure ashing
with appropriate
fasteners
Ceiling
Figure 21. Pitched Roof
CONNECT OUTER
FLUE SHIELD
INNER FLUE PIPE
VENT COLLAR
MOUNTING
FLANGE
Figure 22. Combustion Air Pipe Connection
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