Finned copper tube gas boilers & water heaters – Boiler Manual
5
Table 3 Intake Air Pipe Sizing
Model
For Vertical
For Horizontal
Size
(Up to 60’)
(Up to 60’)
in
mm
in
mm
500
8
203
6
152
750
8
203
6
152
1000
8
203
6
152
1250
10
254
8
203
1500
10
254
10
254
1750
12
305
12
305
2000
12
305
12
305
All joints in metal intake air systems must be secured using corro-
sion resistant fasteners and sealed using a suitable Silicone caulk.
If PVC or CPVC is used, the joints must be cleaned with a suitable
solvent and connected using a solvent based PVC cement.
The
combustion air system MUST be supported by the building
structure not the boiler/water heater.
A combustion air damper interlocked with the unit
should be installed in the intake air pipe when the
infiltration of subfreezing air could occur, otherwise
the unit could freeze up voiding the warranty!
Intake Air Option – Vertical Guidelines
The maximum equivalent length for the vertical intake air pipe is
60 ft
,
18.3 m
. Each 90° elbow and the intake air terminal are equal
to
10 linear ft
,
3.0 m
of pipe, see Table 3.
An approved, nonrestrictive intake air terminal must be used. The
intake air terminal must terminate as shown in Figure 3. The
penetration point in the roof must be properly flashed and sealed.
Intake Air Option – Horizontal Guidelines
The maximum equivalent length for the horizontal intake air pipe
is
60 ft
,
18.3 m
. Each 90° elbow and the intake air terminal
are equal to 10 linear ft, 3.0 m of pipe. If horizontal runs exceed
5 ft
,
1.5 m
they must be supported at
3 ft
,
0.9 m
intervals with
overhead hangers. The certified intake air terminal from RBI must
be used, see Figures 1, 2 and 4.
GENERAL VENTING GUIDELINES
The vent installation must be in accordance with Part
7, Venting of Equipment, of the National Fuel Gas
Code, ANSI Z223.1/NFPA 54-latest revision or appli-
cable provisions of the local building codes. Canadian
installations must comply with CAN/CGA B149.1
or .2 Installation Code. Improper venting can result
in excessive levels of carbon monoxide which can
result in severe personal injury or death!
All vent systems must be fully supported by the building structure
and not by the boiler/water heater. Appropriate thimbles and fire-
stops must be used where required.
Common vent systems must be properly engineered
and sized to provide a negative draft of .03 in, 0.8 mm
to .1 in, 2.5 mm W.C. at the flue outlet. Common
positive pressure vent systems are not to be used.
Improper installation can result in excessive levels of
carbon monoxide which can cause severe personal
injury or death!
VENT SYSTEM OPTIONS – (CATEGORY I, II, IV)
Correctly identify the type of vent system the appliance
requires before proceeding. Category identification is
noted on the unit rating plate.
The flue products in a
Category II and IV
vent system may be
cooled below their dew point and form condensate in the flue. The
materials used for a
Category II and IV
vent must be resistant
to any corrosive damage from flue gas condensate. The flue from
a
Category II and IV
vent system must have a condensate drain
with provisions to properly collect and dispose of any condensate
that may occur in the venting system.
The Futera III may be vented the following ways:
1)
Direct Vent, Positive Pressure, Category IV
uses a vent
system certified to UL 1738 for installations in the United
States, ULC S636 for installations in Canada. Combustion air
is piped from the outdoors to the blower inlet.
2)
Side Wall Vent, Positive Pressure, Category IV
uses a
vent system certified to UL 1738 for installations in the
United States, ULC S636 for installations in Canada. Combus-
tion air is obtained from the space in which the unit is installed.
3)
Vertical/Chimney Vent, Negative Pressure, Category II
uses a metal chimney system approved for Category II.
4)
Vertical Vent, Positive Pressure, Category IV
uses a vent
system certified to UL 1738 for installations in the United States,
ULC S636 for installations in Canada. Combustion air is
obtained from the outdoors or the space in which the unit is
installed.
5)
Vertical Vent/Chimney Vent (750-2000), Negative Pres-
sure Non-Condensing, Category I
uses an approved metal
chimney system or masonry chimney. Combustion air is ob-
tained from the space in which the unit is installed.
All venting and combustion air material supplied by
installer. All venting materials must be approved for the
application. Consult the vent manufacturer’s product
literature.
The maximum equivalent length for the flue outlet vent
system for Category IV conditions is
60 ft
,
18.3 m
.
Use Table 4 for the equivalent lengths per fitting.
Table 4 “Category Equivalent Length Per Fitting”
chart is meant as a guideline for preliminary sizing.
If vent length approaches 75% of maximum length
listed an engineered vent system calculation must be
performed, consult factory.
