RBI Futera II Modulation, Installation And Operation Instructions Manual

Page: 6 / 44

Finned copper tube gas boilers & water heaters – Boiler Manual
6
DIRECT VENT, POSITIVE PRESSURE,
CATEGORY IV
In this configuration the boiler/water heater blower is used
to push the flue products to the outdoors while drawing combustion
air from the outdoors. The Intake Air Option instructions under
the “COMBUSTION AIR & VENTILATION” section must be
followed! The vent system must be sized per Table 4.
Table 4 Category IV
Horizontal Direct Vent Systems
Figures 1 & 2
The vent materials used in horizontal vent systems must be certified
to UL 1738 for installations in the United States, ULC S636 for
installations in Canada. The certified vent terminal from RBI must
also be used.
If any part of a single wall metal vent system passes through an
unheated space, it must be insulated with insulation rated for
400°F
,
204°C . Structrual penetrations must be made using approved fire-
stops. For best results, horizontal vent systems should be as short
and straight as possible.
The vent system must be both gas tight and watertight. All seams
and joints in metal pipes must be joined and sealed in accordance
with the vent system manufacturer’s instructions.
When horizontal vent runs exceed 5 ft , 1.5 m they must be supported
at
3 ft
,
0.9 m
intervals with overhead hangers. The vent system
must be pitched down, toward the vent terminal, 1/4 in/ft , 20 mm/m.
If any part of a single wall metal vent system passes through an
unheated space it must be insulated with insulation rated for 400°F ,
204°C
.
Horizontal vent systems shall terminate at least 4 ft , 1.2 m below,
4 ft
,
1.2 m
horizontally from or
1 ft
,
0.30 m
above any door, window
or gravity air inlet into any building. It must not terminate less than
4 ft
,
1.2 m
horizontally from, and in no case above or below, unless
a 4 ft , 1.2 m horizontal distance is maintained, from electric meters,
gas meters, regulators and relief equipment and not less than
7 ft
,
2.1 m above adjacent public walkway. The bottom of the vent
terminal(s) shall be located at least
5 ft
,
1.5 m
above the air intake
terminal(s) unless there is a minimum 5 ft , 1.5 m horizontal
separation between them. Avoid terminal locations likely to be
affected by winds, snowdrifts, people and pets. Protect building
materials and vegetation from degradation caused by the flue gases.
Vertical Direct Vent Systems – Figure 3
If any part of a single wall metal vent system passes through an
unheated space, it must be insulated with insulation rated for
400°F
,
204°C
. Structural penetrations must be made using approved fire-
stops.
An approved, nonrestrictive vent terminal must be used The top
of a vertical vent system must extend at least
5
1
/
2
ft
,
1.7 m
above
the roof surface and maximum snow line that it passes through,
4 ft
,
1.2 m
above the intake air terminal, see Figure 3.
In addition the vent system must conform to the dimensions shown
in Figure 3. The penetration point in the roof must be properly
flashed and sealed.
The vent system must be gas tight. All seams and joints in metal
pipes must be joined and sealed in accordance with the vent system
manufacturer’s instructions.
Combination Direct Vent Systems – Figure 4
The boiler/water heater can be vented vertically with the intake
air piped horizontally through an outside wall. Follow the instruct-
ions in the Intake Air Option – Horizontal Guidelines on page
5. Also follow the general instructions in the “COMBUSTION
AIR & VENTILATION” and “GENERAL VENTING GUIDE-
LINES” sections.
Model/
Outlet Diameter
Equivalent Feet of Straight Pipe (ft)
K 500 750 1000
5" 5" 6"
Standard Tee 1.25 15 ft 20 ft 25 ft
Boot Tee 0.65 10 ft 10 ft 15 ft
Cap - Low Res. (UL) 0.50 10 ft 10 ft 10 ft
45° w/Bird Screen 0.40 7 ft 7 ft 10 ft
Elbow – 90° 0.38 10 ft 10 ft 10 ft
Elbow – 45° 0.15 5 ft 5 ft 5 ft
Model/
Outlet Diameter
Equivalent Feet of Straight Pipe (ft)
K 1250 1500 1750 2000
6" 8" 10" 10"
Standard Tee 1.25 25 ft 35 ft 40 ft 40 ft
Boot Tee 0.65 15 ft 15 ft 20 ft 20 ft
Cap - Low Res. (UL) 0.50 10 ft 10 ft 15 ft 15 ft
45° w/Bird Screen 0.40 10 ft 10 ft 10 ft 10 ft
Elbow – 90° 0.38 10 ft 10 ft 15 ft 15 ft
Elbow – 45° 0.15 5 ft 5 ft 5 ft 5 ft