Finned copper tube gas boilers & water heaters – Boiler Manual
11
Table 5a Category III Vent Pipe Diameter
Horizontal vent systems shall terminate at least
4 ft
,
1.2 m
below,
4 ft
,
1.2 m
horizontally from or
1 ft
,
0.3 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
from any 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, snow drifts, people and pets. Protect building
materials and vegetation from degradation caused by the flue gases.
Vertical Direct Vent Systems - See Figure 6
The maximum length for the vertical vent and combustion air
pipes is
35 ft
,
10.7 m
plus two 90° elbows for each. 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
. Structual
penetrations must be made using approved fire-stops.
A listed, nonrestrictive vent cap 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 that it passes through,
4 ft
,
1.2 m
above the intake air cap,
see Figure 6.
HORIZONTAL VENT, NEGATIVE PRESSURE,
CATEGORY I
In this configuration a wall-mounted power venter must be used
to pull the flue products horizontally from the unit and vent them
to the outdoors, see Figures 3, 4 & 5. The air for combustion is taken
from the space in which the unit is installed, or from the outdoors.
The applicable instructions under the “COMBUSTION AIR &
VENTILATION” section must be followed!
To maximize the performace of single wall sheet metal vent systems
locate 90° elbows as far from the boiler as possible and from one
another. For best results, horizontal vent systems should be as short
and straight as possible.
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
,
0.3 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
from any 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 vegatation from degradation caused by the flue gases.
To determine the appropriate power venter for the boiler/water
heater, see Table 6, Power Venter Sizes. Follow the power venter
manufacturer’s installation instructions.
Table 6 Power Venter Sizes
Dominator
Power Venter
Max. Pipe Length
Model
Model
ft
mm
300
HS-1
30*
9
400
HS-2
100
31
600
HS-2
67**
21
750-900
HS-3
100
31
1050-1350
HS-4
100
31
1500-2100
HS-5
100
31
*Choose HS-2 100 ft,
31 m
, Max. Pipe Length.
**Choose HS-3 for 100 ft,
31 m
, Max. Pipe Length.
OUTDOOR VENTING
When installed outdoors the Dominator must be fitted with the
factory supplied outdoor vent hood and air intake hood, see Figure
8. Multiple units must be spaced per Figure 9.
The boiler/water heater must be at least
10 ft
,
3.0 m
from any door,
window or gravity air inlet into any building and at least
3 ft
,
0.9 m
from any overhang unless local codes dictate differently.
Avoid locations where wind deflection off of adjacent walls, buildings
or shrubbery might cause a down draft. The unit(s) should be
located at least
3 ft
,
0.9 m
from structures. Outdoor installations
are not recommended in areas where the danger of snow blockage
exists.
Do not place the boiler/water heater in a location that
would subject it to runoff from adjacent buildings or
damage may occur voiding the warranty!
Model Size
Pipe Diameter
in
mm
300 - 400
6
152
600 - 750
8
203
900 - 1050
10
254
1350
12
305
1500 - 2100
14
356
Note: Diameters based on a maximum 35 equivalent feet.
