Finned copper tube gas boilers & water heaters – Boiler Manual
11
Table 5a Category III Vent Pipe Diameter
Model Size
Pipe Diameter
in
mm
400
6
152
600 - 750
8
203
1050
10
254
1200 - 1480
12
305
1650 - 2300
14
356
Note: Diameters based on a maximum 35 equivalent feet.
Horizontal vent systems shall terminate at least
4 ft,
1.2 m
below,
4 ft
,
1.2 m
horizontally from or
1 ft
,
0.23 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 vegetation
from degradation caused by the flue gases.
Vertical Direct Vent Systems - Figure 6
The maximum length for the vertical vent and combustion air pipes
is
35 ft
,
10.7 m
plus two 90° elbows. 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.
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 performance 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
,
0.23 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
,
2.3 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 vegetation from degradation caused
by the flue gases.
To determine the appropriate power venter for the boiler/water
heater, see Table 6. Follow the power venter manufacturer’s
installation instructions.
Table 6 Power Venter Sizes
LCD
Power Venter
Max. Pipe Length
Model
Model
ft
mm
400
HS-2
100
31.0
600
HS-2
67**
20.8
750
HS-3
100
31.0
1050-1200
HS-4
100
31.0
1480-2300
HS-5
100
31.0
**Choose HS-3 for 100 ft,
31 m
, Max. Pipe Length
OUTDOOR VENTING
When installed outdoors the LCD 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
,
3.1 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 downdraft. 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!
