Sterling GG-120 User Manual

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VENTING (continued)
AIR INLET COLLAR
Remove screen and mounting plate from air inlet on 
rear panel of unit by removing 4 screws. Secure inlet 
collar and gasket to inlet opening re-using the 4 screws 
removed in step one.
EXHAUST AIR COLLAR
Secure 5-4” reducer to flue collar on rear panel of 
unit sizes 090, 105 and 120. Seal per exhaust venting 
instructions.
VERTICAL TERMINATION
Select location on roof for vent terminal, ensuring 
adequate space inside the building/structure for 
concentric vent box. Terminal must be at least 6 feet 
(1.8m) from any wall or adjoining building. See Figure 
22.
Cut a hole through the roof for combustion air pipe. 
Concentric vent box is to be suspended from the 
underside of the roof using suitable brackets (field 
supplied). Before mounting box, cut a length of 6 inch 
(152mm) (sizes 030-075) or 8 inch (203mm) (sizes 
090-120) pipe so that dimension A, Figure 22, is equal 
to the dimension from the top of the box to the roof 
surface plus 20 inches or plus maximum expected 
snow depth, whichever is greater. Fasten pipe to 
combustion air inlet connection of concentric vent box 
and seal joint. Insert pipe through roof and fasten vent 
box in place. Flash and/or caulk pipe to roof. Install inlet 
air screen assembly and fasten to pipe with screws. 
Insert a 5 foot length of Type B vent pipe through the 
concentric vent box opening (detail A, Figure 20) with 
the "UP" arrow pointing up. Position the pipe to extend 
12 inches beyond the inlet air screen. Secure the Type 
B vent pipe in position by drilling three small equally 
spaced holes through the collar of the concentric vent 
box and inserting sheet metal screws. Install defl ector 
disk on Type B vent pipe 2-1/2 inches above inlet air 
screen and fasten with screws. Seal joint between 
defl ector disk and pipe with silicone sealant. Install vent 
terminal on top of Type B vent pipe, fasten with screws 
and seal joint.
Connect flue pipe and combustion air pipe from 
concentric vent box to unit, following instructions on 
pages 26 and 27. Joint between Type B vent pipe 
and single wall vent pipe must be sealed with high 
temperature silicone sealant. (See Figure 21) Collars 
on unit and on concentric vent box are sized so that 
crimped ends of combustion air pipes go toward the 
unit and crimped ends of flue pipes go away from the 
unit.
HORIZONTAL TERMINATION
Select a location on outside wall for vent terminal. In 
most applications, the terminal should be on level with 
the fl ue outlet of the unit less a 1/4 inch per foot pitch 
for condensate drainage toward the outside of the 
building. See Figure 23.
The location of the vent terminal must be in accordance 
with the National Fuel Gas Code ANSI Z223.1 in the U.S. 
or the Natural Gas Installation Code CAN/CGA-B149.1 
or the Propane Gas Installation Code CAN/CGA-149.2 
in Canada. See Table 4 for minimum clearances. In 
Canada, a vent shall not terminate above a meter/
regulator assembly within 3 feet (.9m) horizontally of 
the vertical centerline of the regulator nor within 6 feet 
(1.8m) of any gas service regulator vent outlet.
Cut a hole through the wall for a 6 inch (152mm) sizes 
(030-075) or 8 inch (203mm) sizes (090-120) combustion 
air pipe. Install thimble if required by local codes or 
type of wall construction. Concentric vent box may be 
fastened directly to wall or spaced away from wall using 
suitable brackets (fi eld supplied). Cut a length of pipe so 
that it will protrude 4 inches (102mm) through the wall 
when the box is mounted in position. Fasten pipe to box 
with sheet metal screws, using at least three screws per 
joint. Seal joint with silicone sealant. Insert pipe through 
wall and fasten adapter box in place so that the pipe 
pitches downward 1/4 inch per foot (21mm/m) toward 
the outside. Flash and/or caulk pipe on outside wall. 
Install inlet air screen assembly and fasten to pipe with 
screws. Insert a 3 foot length of 4 inch (sizes 030-075) 
or 5 inch (sizes 090-120) Type B vent pipe through the 
concentric vent box opening (detail A, Figure 20) with 
the "UP" arrow pointing toward the outside. Position the 
pipe to extend 12 inches beyond the inlet air screen. 
Secure the Type B vent pipe in position by drilling three 
small equally spaced holes through the collar of the 
concentric vent box and inserting sheet metal screws. 
Install defl ector disk on Type B vent pipe 2-1/2 inches 
(63.5mm) from inlet air screen and fasten with screws. 
Install vent terminal on end of Type B vent pipe, fasten 
with screws and seal joint.
Connect fl ue pipe and combustion air pipe from concentric 
vent box to unit, following instructions on pages 26 
and 27. Joint between Type B vent pipe and single 
wall vent pipe must be sealed with high temperature 
silicone sealant. (See Figure 21) Collars on unit and on 
concentric vent box are sized so that crimped ends of 
combustion air pipes go toward the unit and crimped 
ends of fl ue pipes go away from the unit.
SEPARATED COMBUSTION