5-565.1
6
7. Avoid venting through unheated space. When venting does
pass through an unheated space, insulate runs greater than
5 feet to minimize condensation. Inspect for leakage prior to
insulating and use insulation that is noncombustible with a
rating of not less than 350°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 7.1.
note: A vent is the vertical passageway used to convey
flue gases from the unit or the vent connector to the outside
atmosphere. A
vent connector is the pipe which connects the
unit to a vent or chimney. Vent connectors serving Category
I appliances shall not be connected into any portion of
mechanical draft systems operating under positive pressure.
table 6.1 - vertical category i vent sizing requirements
WARNING
table 6.2 - ansi venting requirements
appliance
venting
category
description
requirements
i
Negative vent pressure
Follow standard venting
Non-condensing
requirements.
ii
Negative vent pressure
Condensate must be
Condensing
drained.
iii
Positive vent pressure
Vent must be gastight.
Non-condensing
iv
Positive vent pressure
Vent must be liquid and
Condensing
gastight. Condensate must
be drained.
installation
venting
1. Gas fired heating equipment must be vented - do not
operate 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 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.
model size
vent connector
diameter
minimum vent Pipe
diameter
75-125
4"
4"
150-175
4"
5"
➀
200
6"
6"
225-400
6”
6”
➀
Requires a 4" to 5" adapter for the larger vent pipe diameter.
4. For Category I vent systems limit length of horizontal runs to
75% of vertical height. Install with a minimum upward slope
from unit of 1/4 inch per foot and suspend securely from
overhead structure at points no greater than 3 feet apart.
For best venting, put vertical vent as close to the unit as
possible. A minimum of 12" straight pipe is recommended
from the power exhauster outlet before turns in the vent
system. Fasten individual lengths of vent together with at
least three corrosion-resistant sheet-metal screws.
5. It is recommended that vent pipes be fitted with a tee with a
drip leg and a clean out cap to prevent any moisture in the
vent pipe from entering the unit. The drip leg should be inspected
and cleaned out periodically during the heating season.
6. The National Fuel Gas Code requires a minimum clearance
of 6 inches from combustible materials for single wall vent
pipe. 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 inches if heat damage
other than fire (such as material distortion or discoloration)
could result.
general venting instructions
1. Installation of venting must conform with local building codes,
or in the absence of local codes, with the National Fuel Gas
Code, ANSI Z223.1 (NFPA 54) - Latest Edition. In Canada,
installation must be in accordance with CAN/CGA-B149.1 for
natural gas units and CAN/CGA-B149.2 for propane units.
2. All vertically vented units are Category I. All horizontally vented
units are Category III. The installation must conform to the
requirements from Table 6.2 in addition to those listed below.
3. For units vented as Category I, refer to Table 6.1 for vent
sizing. Vent sizing for units vented as Category III are covered
in a later section on page 7. Do not use a vent pipe smaller
than the size of the outlet or vent transition of the appliance.
The pipe should be suitable corrosion resistant material.
Follow the National Fuel Gas Code for minimum thickness
and composition of vent material. The minimum thickness for
connectors varies depending on the pipe diameter.
8. When the vent passes through a combustible wall or floor,
a metal thimble 4 inches greater than the vent diameter is
necessary. If there is 6 feet 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 inches greater than the diameter of the vent pipe. If a
thimble is not used, all combustible material must be cut
away to provide 6 inches of clearance. Any material used
to close the opening must be noncombustible.
9. Do NOT use dampers or other devices in the vent pipes.
10. Precautions must be taken to prevent degradation of
building materials by flue products.
11. For category I vent systems the outlet of the vent should
extend as shown in Figure 7.1 and Table 7.1 if the following
conditions are met:
• Vent diameter is less than 12 inches, vent is of double
wall construction and is a listed product, and the vent
does not terminate within 2' of a vertical wall or similar
obstruction.
• For vents that have a diameter of 12 inches or larger,
constructed of single wall, or terminate within 2' of a
vertical wall or similar obstruction, the vent pipe shall
extend at least 2' higher than any portion of a building
within a horizontal distance of 10' (refer to Figure 7.1).
12. Use a listed vent terminal to reduce downdrafts and
moisture in vent.
13. For instructions on common venting refer to the National
Fuel Gas Code.
14. The vent must terminate no less than 5' above the vent
connector for Category I vent systems.
15. A unit located within an unoccupied attic or concealed space
shall not be vented with single wall vent pipe.
16. Single wall vent pipe must not pass through any attic, inside
wall, concealed space, or floor.
17. Do NOT vent this appliance into a masonry chimney.
18. When condensation may be a problem, the venting system
shall not terminate over public walkways or over an area
where condensation or vapor could create a nuisance or
hazard or could be detrimental to the operation of regulator
relief openings or other equipment.
19. In cold ambient conditions, such as Canada, the following
items are recommended for proper operation and
equipment life:
• The vent pipe must not pass through an unheated space
or interior part of an open chimney unless the vent pipe is
insulated.
• Where the vent pipe may be exposed to extreme cold, or
come into contact with snow or ice, the entire vent must
be insulated or double wall (includes outdoors). It is
preferred that the double wall vent is one continuous
piece but a joint is allowed outside the building.
• The heater system shall be checked at least once a year
by a qualified service technician.
