All Air From Inside The Building - RBI FUTERA XLF Series Installation And Operation Instructions Manual

All air from inside the building

If the Futera XLF is to be located in a confi ned space, the minimum
clearances listed in Table 1, page 4 must be maintained between it
and any combustible construction. When installed in a confi ned
space without the intake air option (as in Figure 5, page 10 through
Figure 8, page 13) two permanent openings communicating with
an additional room(s) are required. The combined volume of
these spaces must have suffi cient volume to meet the criteria for an
unconfi ned space. Th e total air requirements of all gas utilization
equipment, fireplaces, wood stoves or any type of exhaust fan
must be considered when making this determination. Each
opening must have a minimum free area of 1 in
2200 mm 2 /kW based on the total input rating of ALL gas utilization
equipment in the confi ned area. Each opening must be no less than
100 in 2 , 64,516 mm 2 in size. The upper opening must be within
12 inches, 305 mm of, but not less than 3 inches, 76 mm from, the
top of the enclosure. Th e bott om opening must be within 12 inches,
305 mm of, but not less than 3 inches, 76 mm from, the bott om of
the enclosure.
All air from outside the building
When installed in a confi ned space without utilizing the intake air
option two permanent openings communicating directly with, or
by ducts to, the outdoors or spaces that freely communicate with
the outdoors must be present. Th e upper opening must be within
12 inches, 305 mm of, but not less than 3 inches, 76 mm from, the
top of the enclosure. Th e bott om opening must be within 12 inches,
305 mm of, but not less than 3 inches, 76 mm from, the bott om of
the enclosure.
Where directly communicating with the outdoors or communicating
with the outdoors through vertical ducts, each opening shall have a
minimum free area of 1 in 2 /4000 Btu/hr, 550 mm
input rating of all of the equipment in the enclosure.
Where communicating with the outdoors through horizontal ducts,
each opening shall have a minimum free area of 1 in
1100 mm 2 /kW of the total input rating of all of the equipment in
the enclosure.
When ducts are used, they must have the same cross-sectional area
as the free area of the opening to which they connect.
When calculating the free area necessary to meet the make-up air
requirements of the enclosure, consideration must be given to the
blockage eff ects of louvers, grills and screens. Screens must have a
minimum mesh size of 1/4 inch, 6.4 mm. If the free area through a
louver or grill is not known, ducts should be sized per Table 2.
Canadian installations must comply with CSA B149.1 when air
supply is provided by natural air fl ow from the outdoors for natural
draft , partial fan-assisted, fan-assisted, or power draft -assisted burners,
there shall be a permanent air supply opening(s) having a cross-
sectional area of not less than 1 in
kW) up to and including 1 million Btuh, plus 1 in
(155 mm 2 per kW) in excess of 1 million Btuh.
F F Finned copper tube gas boilers & water heaters – Boiler Manual F d b
2 /1000 Btu/hr,
2 /kW of the total
2
/2000 Btu/hr,
2 per 7,000 Btuh (310 mm 2 per
2
per 14,000 Btuh
b l & h B l M
Table 2 Make-up Air Louver Sizing
Input Required cross-sectional area
MBH
Wire screen
¼ inch (6.4 mm)
2 2
in cm
2500 625 4031
3000 750 4838
3500 875 5645
4000 1000 6452
Intake air option — General guidelines
Th is confi guration provides combustion air directly to the boiler/
water heater's air intake adapter using a dedicated pipe when using
the direct vent option. Combustion air can be drawn in horizontally
through the same outside wall which terminates the exhaust gases
or vertically through the roof, see Figure 1, page 8 through Figure 4,
page 9.
Common intake air systems may be used provided the
common duct is sized properly. An intake combustion
air damper should be installed if the common vent
option is used in the intake air pipe of each heater.
Improper installation can result in excessive levels of
carbon monoxide which can cause severe personal
injury or death!
Table 3 Intake air pipe sizing
Input Vertical
MBH
in
2500/3000 10
3500/4000 12
All joints in metal intake air systems must be secured using
corrosion 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.
Th e 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
infi ltration of subfreezing air could occur, otherwise
the unit could freeze up voiding the warranty!
Intake air option – Vertical guidelines
Th e maximum equivalent length for the vertical intake air pipe is
o
100 ft , 30.5 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. Th e
intake air terminal must terminate as shown in Figure 3, page 9. Th e
penetration point in the roof must be properly fl ashed and sealed.
l
Metal louvers Wooden louvers
75% free area 25% free area
2 2 2
in cm in cm
833 5382 2500 16127
1000 6452 3000 19354
1167 7522 3500 22581
1334 8592 4000 25808
Horizontal
mm in mm
254 8 203
305 10 254
5
2