RBI Dominator Series Installation & Operating Instructions Manual 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 of 1 in
the total 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 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, ducts should be sized per Table 3.
Table 3 Make-up Air Louver Sizing
Required Cross Sectional Area
Input 1/4 in 6.4 mm
Wire Screen
(MBH)
2 2
in cm
300 75 484
400 100 645
600 150 968
750 188 1210
900 225 1452
1050 263 1694
1350 338 2177
1500 375 2419
1950 488 3145
2100 525 3387
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
(310 mm 2 per kW) up to and including 1 million Btuh, plus
2 per 14,000 Btuh (155 mm
1 in
Btuh.
6
Finned copper tube gas boilers & water heaters – Boiler Manual F F Fi d b
2 /4000 Btu/hr, 550 mm 2 /kW of
2
/2000 Btu/hr,
75% Free Area 25% Free Area
Metal Louvers Wooden Louvers
2 2 2
in cm in cm
100 645 300 1935
133 860 400 2581
200 1290 600 3871
250 1613 750 4839
300 1935 900 5806
350 2258 1050 6774
450 2903 1350 8710
500 3226 1500 9677
650 4194 1950 12,581
700 4516 2100 13,548
2
per 7,000 Btuh
2 per kW) in excess of 1 million
b il & h
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 the same outside wall which terminates the exhaust gases or
vertically through the roof, see Figures 4, 5, 6 & 7.
Common intake air systems may be used provided
the common duct is sized properly and an intake
combustion air damper is installed 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!
Single wall galvanized smoke pipe, single wall aluminum pipe or
flexible aluminum pipe can be used for the intake air pipe. It must be
sized per Table 4. All joints in metal combustion air systems must be
secured using corrosion resistant fasteners and sealed using a suitable
Silicone caulk. The combustion air system MUST be supported
by the building structure not the boiler/water heater.
Table 4 Intake Air Pipe Sizing
Model Size
300 & 400
600 & 750
900 & 1050
1350 - 2100
2
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!
Intake Air Option - Horizontal Guidelines
The maximum equivalent length for the horizontal combustion
air pipe on installations that used the Direct Vent option is 35 ft,
10.8 m. The maximum equivalent length for the horizontal
combustion air pipe on installations that use the Horizontal Power
Vent option is 100 ft, 30.5 m. Each 90° elbow and the combustion
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 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.
B il M l
Pipe Diameter
in
8
8
10
12
mm
203
203
254
305