Install Instructions (Venting)

25
3.0 Direct Vent Installation of Vent/Air Piping
SECTION III - CATEGORY IV (INDOOR AIR)
INSTALLATION OF VENT/AIR PIPING
A Category IV appliance utilizes uncontaminated indoor or
outdoor air (surrounding the appliance) for combustion.
3.1 Category IV - Vertical - Through the Roof
or Unused Chimney
The installation must conform to the requirements of
the authority having jurisdiction or, in the absence
of such requirements, to the National Fuel Gas
Code, ANSI Z223.1/ NFPA 54, and/or Natural Gas and
Propane Installation Code, CAN/CSA B149.1.
When using an inoperative chimney as a means of a
chase for the vent, the surrounding space within the
chimney cannot be used to draw combustion air or
vent another appliance.
A gas vent extending through a roof should not ter-
minate near an adjacent wall or below any building
extensions such as roof eaves, balconies or decks.
Failure to comply with the required clearances in
this manual could result in severe personal injury,
death or substantial property damage.
The information and diagrams outlining the fittings
and method of terminating the vent/combustion air
are directly related to PVC/CPVC vent systems.
When utilizing an AL 29-4C
®
or Polypropylene vent
system there maybe some variations. Consult the
appropriate vent manufacturer for recommenda-
tions and clarifications.
3.1.1 Determine Termination Location
Locate the vent and combustion air termination using the
following guidelines:
1. The total length of the vent must not exceed the limits
given in Table 8 on page 8.
WARNING
NOTICE
NOTICE
NOTICE
Do not include the coupling used to terminate the
v
ent exterior of the building when determining the
total length of pipe.
2
. The combustion air piping must terminate at the boil-
er with a 90º elbow.
3. The vent must terminate vertically with a coupling
and must be located 12” [30.5 cm] (18” [45.7 cm]
Canada) above the highest anticipated snow level
as shown in Fig. 14.
4. The following should be considered when determin-
ing the location of the vent termination:
a. Locate the vent termination where flue vapors
will not damage surrounding shrubs, plants or
air conditioning equipment or be objectionable
to the homeowner.
b. The flue products will form a noticeable plume
as they condense in colder air. Avoid terminat-
ing the vent in areas where the plume could
obstruct window views.
c. Prevailing winds could cause freezing of flue
condensation and a buildup of water / ice on sur-
rounding plants or building surfaces.
d. Avoid locations where prevailing winds could
affect the performance of the boiler or cause
recirculation of the flue gases, such as inside
corners of buildings or near adjacent buildings
or vertical surfaces, window wells, stairwells,
alcoves, courtyards, or other recessed areas.
NOTICE
Vent Termination
1
2
"
[
3
0
.
5
c
m
]
(
1
8
”
[
4
5
.
7
c
m
]
C
a
n
a
d
a
)
A
b
o
v
e
t
h
e
H
i
g
h
e
s
t
A
n
t
i
c
i
p
a
t
e
d
S
n
o
w
L
e
v
e
l
Category - IV - Vertical Termination of
Vent Pipe
Fig. 14: