York DFAH User Manual
Page 15
107272-UIM-B-1105
Unitary Products Group
15
EXTERIOR ROOF JACK EXTENSION
Application
Available to comply with instances in which the roof jack crown needs to
be raised to meet a roof clearance requirement. One extension will
raise the roof jack crown by 18” 45.7 cm).
ROOF JACK
EXISTING FURNACE REPLACEMENT
If this furnace replaces an existing furnace, do the following:
1.
If a 2nd roof, roof cap or addition has been made to the existing
roof of the home, remove the old roof jack completely! To avoid the
possibility of an improperly installed pipe or gaps in the old roof
jack, INSTALL A NEW ROOF JACK. Your ceiling and roof height
will determine the correct roof jack to use.
2.
After unpacking the roof jack, check the rain caps. Insure they are
not damaged, tilted or crooked. Do not twist, crush or sit on the
roof caps during installation. Damaged roof caps will cause
improper furnace operation. The furnace will not heat properly and
could result in explosion.
3.
Before inserting the roof jack into the furnace top, inspect the fur-
nace flue and combustion air opening for debris or insulation
which might have fallen in during pre-installation steps. Do not pro-
ceed unless all debris has been cleaned out or removed.
4.
After installing roof jack on furnace top collar, check to make sure
there is no gap in back or side between the pipe collar and the fur-
nace casing top.
5.
Use only the pipes provided with the roof jack assembly. Do not
add to or adapt other sheet metal pipes. Do not cut, insert or add
other pipes to this assembly.
6.
In no case should there be a gap between sections of the flue pipe
or the combustion air pipe. If necessary to prevent excessive air
leakage, the installer should seal joints in the combustion air tube
with Chemcaulk 900 sealant or other suitable sealant.
NEW HOME INSTALLATION
If this furnace is installed in a new home do the following:
1.
Inspect the furnace top collars for signs of insulation or ceiling
debris which might have fallen in during cutting of the ceiling and
roof holes. Remove all debris before continuing.
2.
After unpacking the roof jack, check the rain caps. Insure they are
not damaged, tilted or crooked. Do not twist, crush or sit on the
roof caps during installation. Damaged roof caps will cause
improper furnace operation. The furnace will not heat properly and
could result in explosion.
3.
Before inserting the vent pipe into the furnace top, inspect the fur-
nace flue and combustion air opening for debris or insulation
which have fallen in during pre-installation steps. Do not proceed
unless all debris have been cleaned out or removed.
4.
After installing roof jack on furnace top collar, check to make sure
there is no gap in back or side between the pipe collar and the fur-
nace casing top. If necessary to prevent excessive air leakage, the
installer should seal joints in the combustion air tube with Chem-
caulk 900 sealant or other suitable sealant.
INSTALLATION IN SNOW REGIONS
When the combustion air pipe inlet is covered or blocked with snow, the
furnace will not operate properly due to the depleted combustion air
supply.
Therefore, if the furnace will be located in regions where snow accumu-
lation on the roof exceeds 4" or in H.U.D. Snow Load Zones, a roof jack
extension and PVC combustion air inlet extension is recommended.
Refer to Figure 26 or 27.
COMBUSTION AIR INLET
All combustion air pipe and fittings must conform to American National
Standards Institute (ANSI) standards and American Society for Testing
and Materials (ASTM) standards D1785 (Schedule 40 PVC), D2665
(PVC-DWV), F891 (PVC-DWV cellular core). D2241 (SDR-21 and
SDR-26 PVC), D2261 (ABS-DWV), or F628 (Schedule 40 ABS. Pipe
cement and primer must conform to ASTM Standards D2564 (PVC) or
D2235 (ABS).
1.
Mark vertical combustion air inlet centerline on ceiling. Cut hole for
combustion air inlet piping. Clearance to combustible materials is
not required.
2.
Cut hole in roof. Provide minimum 12” (30.5 cm) vertical separa-
tion between combustion air inlet pipe and roof jack vent cap.
Clearance to combustible materials is not required.
3.
Route piping through ceiling and holes. Provide firestop as
required.
4.
Insert combustion air inlet coupling into casing. See Figure 26 or
27.
5.
Slide PVC pipe into coupling. Use a hose clamp to secure the PVC
pipe to the coupling.
6.
Complete piping through roof. Provide flashing at roof penetration.
7.
Prepare elbow assembly. See Figure 25. Insert screen into elbow
socket. Secure in place with street elbow (or nipple).
8.
PVC pipe can be straight through the roof or it can be offset by
using up to 4-90° elbows. Horizontal PVC pipe can be up to 10 ft.
(3.1 m) long in any direction from the furnace vent connection. Ver-
tical PVC pipe can be up to 10 ft. (3.1 m) in length.
9.
Attach elbow assembly to combustion air inlet piping. See Figure
26 or 27. Inlet must be minimum 6” (15.2 cm) above highest antic-
ipated snow level, but no more than 24” 61.0 cm) above roof.
Failure to follow all venting instructions can result in fire,
asphyxiation, or explosion.
Only use the appropriate roof jack. See Figures 26, 27,
30, and 31 for correct application.
Do not exceed the maximum height as determined from
Table 9. Installer should allow an additional 1-1/2" (3.8
cm) travel before the flue pipe assembly is fully extended
against the built-in stop. This provides an additional safe-
guard against the flue assembly being pulled from the roof
jack during transportation or other stress conditions.
The vent and combustion air openings in the top of the furnace
must be free of construction debris before the Roof Jack is
installed. Failure to ensure that these openings are free will result in
excessive amounts of CARBON MONOXIDE and elevated heat
exchanger temperatures which can lead to premature heat
exchanger failure, resulting in a fire or explosion or cause damage
to the furnace or some of its components that will result in property
damage and loss of life.
FIGURE 25: Elbow Assembly
90° Street
Elbow
90°
Elbow
Screen
Pipe to Furnace