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INSTALLATION - VENTING
W ARNING
1. Gas fired heating equipment must be vented - do not
perate unvented.
2. A built-in power exhauster is provided - additional
external power exhausters are not required or permitted.
3. If you are replacing an existing heater, it may be
necessary to resize the venting systems. Improperly
sized venting systems can result in vent gas leakage or
the formation of condensate. Refer to the National Fuel
Gas Code ANSI Z223.1 or CSA B149.1 latest edition.
Failure to follow these instructions can result in serious
injury or death.
4. Under no circumstances should two sections of double
wall vent pipe be joined together within one horizontal
vent system due to the inability to verify complete seal
of inner pipes.
CAUTION
Installation must conform with local building codes or in the
absence of local codes, with Part 7, Venting of Equipment, of
the National Fuel Gas Code, ANSI Z223.1 (NFPA 54) - latest
edition. In Canada installation must be in accordance with
CSA B149.1.
The separated combustion duct furnaces must be vented with
the proper passageway as described in these instructions to
convey flue gases from the unit or the vent connector to the
outside atmosphere. The heaters must also have a separate
combustion air intake pipe to bring in fresh air for combustion
from the outside atmosphere.
The venting instructions are organized in sections, based on
installation type. The sections are identified as follows:
Section
Installation Instructions by Vent System Type
A
General Instructions for ALL installations
VERTICAL 2-PIPE vent systems j
B
C
HORIZONTAL 2-PIPE vent systems j
HORIZONTAL AND VERTICAL CONCENTRIC
D
vent systems j
j T he differences between Vertical and Horizontal vent systems in 2-Pipe or
Concentric Vent configurations will be identified in "Section A - General
Instructions – All Units".
Section A - General Instructions - All Units
A1. If the heater being installed is replacing existing equipment
and using the existing vent system from that equipment,
inspect the venting system for proper size and horizontal
pitch, as required in the National Fuel Gas Code ANSI
Z223.1 or CSA B149.1 Installation Code-latest edition and
these instructions. Determine that there is no blockage or
restriction, leakage, corrosion and other deficiencies, which
could cause an unsafe condition.
A2. The combustion air and vent pipes should be galvanized
steel or other suitable corrosion resistant material. Follow
the National Fuel Gas Code for minimum thickness of vent
material. The minimum thickness for connectors varies
depending on the pipe diameter. Do not vent unit with PVC
or other forms of plastic venting material.
A3. All heaters come with factory installed vent and combustion
air adapters for attaching the pipe to the heater. The pipe
diameters are 4" for model sizes 75-175 and 6" for model
sizes 200-400. All units are classified as Category III
vented appliances, which defined by ANSI is positive
pressure, non-condensing, and requires the vent system to
be gastight. Attach the vent pipe to the adapter with 3
corrosion resistant screws. (Drill pilot holes through the
vent pipe and adapter prior to screwing in place). Vent pipe
must not be smaller than the connector size. Category III
vent systems listed by a nationally recognized agency and
matching the diameters specified may be used. Different
brands of vent materials may not be intermixed.
A4. Limit the total equivalent vent pipe length to a minimum of
5' and a maximum as shown in Table 7.1, making the vent
system as straight as possible. Total equivalent vent pipe
length must include elbows. The equivalent length of a 4"
elbow is 5' and for a 6" elbow is 7'.
Table 7.1 - Individual Total Equivalent Lengths
for Combustion Air and Exhaust Vent Pipes
Model Size
75
100, 125, 150, 175
200, 225
250, 300
350, 400
A5. A minimum of 12" straight pipe is recommended from the
flue outlet before turns in the vent pipe.
A6. Horizontal sections of vent and combustion air pipes are
to be installed with a minimum downward slope from the
appliance of 1/4 inch per foot and suspended securely
from overhead structures at points not greater than 3'
apart.
A7. Fasten individual lengths of vent together with at least
three corrosion resistant sheet metal screws.
A8. Keep single wall vent pipe at least 6" from combustible
materials. For double wall vent pipe, follow the vent pipe
manufacturer's clearances to combustibles. The minimum
distance from combustible materials is based on the
combustible material surface not exceeding 160°F.
Clearance from the vent pipe (or the top of the unit) may
be required to be greater than 6" if heat damage other
than fire could result (such as material distortion or
discoloration).
A9. Avoid venting through unheated space when possible.
When venting does pass through an unheated space or if
the unit is installed in an environment that promotes
condensation, insulate runs greater than 5' to minimize
condensation. Inspect for leakage prior to insulating and
use insulation that is noncombustible with a rating of not
less than 400°F. Install a tee fitting at the low point of the
vent system and provide a drip leg with a clean out cap as
shown in Figure 9.1.
A10. When the vent passes through a combustible INTERIOR
wall or floor, a metal thimble 4" greater than the vent
diameter is necessary. If there is 6' or more of vent pipe
in the open space between the appliance and where the
vent pipe passes through the wall or floor, the thimble
need only be 2" greater than the diameter of the vent pipe.
If a thimble is not used, all combustible material must be
cut away to provide 6" of clearance. Where authorities
have jurisdiction type B vent may be used for the last
section of vent pipe to maintain clearance to combustibles
while passing through wall or floor. See Figure 8.1. Any
material used to close the opening must be
noncombustible.
5-594.10
Minimum (ft)
Maximum (ft)
5
48
5
55
5
70
5
63
5
70
7
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