RBI LCD Series Installation & Operation Manual page 6

Page 6
All Air From Outside The Building
When installed in a confined 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. The upper opening must be within 12 in,
305 mm of, but not less than 3 in, 76 mm from, the top of
the enclosure. The bottom opening must be within 12 in,
305 mm of, but not less than 3 in, 76 mm from, the bottom
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
2 /4000 Btu/hr, 550 mm
of 1 in
rating of all of the equipment in the enclosure.
Where communicating with the outdoors through
horizontal ducts, each opening shall have a minimum
2
free area of 1 in /2000 Btu/hr, 1100 mm
input rating of all of the equipment in the enclosure. When
louvers and screens 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 effects
of louvers, grills and screens. Screens must have a
minimum mesh size of 1/4 in, 6.4mm . If the free area
through a louver or grill is not known the louver or grill
should be sized per Table 2.
Table 2 - Make-up Air Louver Sizing
Required Cross Sectional Area
Input 1/4 in 6.4 mm 75% Free Area
(MBH) Wire Screen
in 2 cm
363
225 57
300 75 484
399 100 645
600 150 968
1210
750 190
900 225 1451
1050 263 1696
1200 300 1936
2388
1480 370
1650 413 2662
1970 493 3179
2300 575 3711
Canadian installations must comply with CSA B149.1
when air supply is provided by natural air flow 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
2
(310 mm per kW) up to and including 1 million Btuh,
plus 1 in 2 per 14,000 Btuh (155 mm
of 1 million Btuh.
LCD INSTALLATION AND OPERATION INSTRUCTIONS
2 /kW of the total input
2
/kW of the total
25% Free Area
Metal Louvers Wooden Louvers
2 in 2 cm 2 in 2
484
75 225
100 645 300
133 858 399
200 1290 600
1613
250 750
300 1935 900
350 2258 1050
400 2580 1200
3182
494 1480
550 3548 1650 10,643
657 4236 1970 12,707
767 4945 2300 14,835
2
per 7,000 Btuh
2 per kW) in excess
Intake Air Option - General Guidelines
This configuration provides combustion air directly to the
boiler/water heater's air intake using a dedicated pipe
to obtain combustion air from the outdoors. Combustion
air can be drawn in horizontally through an outside wall
or vertically through the roof, see Figures 4, 5, 6 & 7.
WARNING: Each boiler/water heater must have
it's own intake air system. Common intake air
systems are not to be used! Improper
installation can result in excessive levels of
carbon monoxide which can cause severe
personal injury or death!
Single wall galvanized smoke pipe, single wall aluminum
pipe or flexible aluminum pipe can be used for the
in-take air pipe. It must be sized per Table 3. All joints
in metal combustion air systems must be secured using
corrosion resistant fasteners and sealed using a suitable
Silicon caulk or tape. The combustion air system
MUST be supported by the building structure not
the boiler/water heater.
Table 3 - Combustion Air Pipe Sizing
Model Size
225 - 300
400
600 - 750
900 - 1050
1200 - 2300
CAUTION: A stack damper interlocked with the unit
should be installed in the intake air pipe when the
infiltration of sub-freezing air could occur, otherwise
the unit could freeze up voiding the warranty!
cm 2
Intake Air Option - Horizontal Guidelines
1452
The Maximum equivalent length for the horizontal
1935
combustion air pipe on installations that used the Direct
2573
Vent option is 35 ft, 10.8 m . The maximum equivalent
3870
length for the horizontal combustion air pipe on
4840
installations that use the Horizontal Vent option is 100 ft,
5805
30.5 m . Each 90° elbow and the combustion air terminal
6773
are equal to 10 linear ft, 3.0 m of pipe. If horizontal runs
7740
exceed 5 ft, 1.5 m they must be supported at 3 ft, 0.9 m
9546
intervals with overhead hangers. The certified combustion
air terminal from RBI must be used and installed as
shown in Figures 4 and 5.
Intake Air Option - Vertical Guidelines
The maximum length for the vertical combustion air
pipe is 30 ft, 9.1 m plus two 90° elbows. A listed,
nonrestrictive combustion air cap must be used. The
combustion air cap must terminate as shown in Figure
6. The penetration point in the roof must be properly
flashed and sealed.
Pipe Diameter
mm
in
5 127
6 152
203
8
254
10
12 305