6
FUTERA FUSION INSTALLATION AND OPERATION INSTRUCTIONS
DIRECT VENT,
POSITIVE PRESSURE, CATEGORY IV
In this confi guration the boiler/water heater blower is used
to push the fl ue 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
Model
Pipe Diameter (Min.)
Size
(Up to 60')
in
mm
500
7
178
750
7
178
1000
7
178
1250
8
203
1500
8
203
1750
10
254
2000
10
254
Horizontal Direct Vent Systems – Figures 1 & 2
The vent materials used in horizontal vent systems must
be certifi ed to UL 1738 for installations in the United States,
ULC S636 for installations in Canada. The certifi ed vent
terminal from RBI must also be used.
The maximum equivalent length for the horizontal vent pipe
is
60 ft
,
18.3 m
.
Each 90˚ elbow and the vent terminal are
equal to
10 linear ft
,
3.0 m
of pipe. 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 fi re-
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 back, towards the secondary
heat exchanger,
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
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
fl ue 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 fi re-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 fl ashed 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 instructions in the Intake Air Option
–
Horizontal
Guidelines. Also follow the general instructions in the
“COMBUSTION AIR & VENTILATION” and “GENERAL
VENTING GUIDELINES” sections.
