Before you start use the following steps to verify
that the venting system is adequately sized:
1. Seal any unused openings in the venting system.
2. Inspect the venting system for proper size and horizontal
pitch, as required in the National Fuel Gas Code ANSI
Z223.1 or CAN/CGA B149.1 or .2 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.
3. In so far as practical, close all building doors and windows
and all doors between the space in which the appliance(s)
connected to the venting system are located and other
spaces of the building. Turn on clothes dryers and any
exhaust fans such as range hoods and bathroom exhausts,
so they shall operate at maximum speed. Do not operate a
summer exhaust fan. Close fireplace dampers.
4. Follow the lighting instructions. Place the appliance being
inspected in operation. Adjust thermostat so that the
appliance will operate continuously.
5. After it has been determined that each appliance connected
to the venting system properly vents when tested as
outlined above, return doors, windows, exhaust fans,
fireplace dampers and any other gas-burning appliance to
their previous conditions of use.
6. If improper venting is observed during any of the above
tests, the venting system must be corrected.
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.
Venting Instructions
1. All vertically vented heaters are category I venting.
All horizontally vented heaters are category I or III
depending on venting. For a unit to be classified vertical,
the horizontal run may not exceed 75% of the vertical rise.
2. Using Table 5.1, determine the venting requirements for the
category determined above. A category III heater must
conform to the venting requirements called out in Table 5.1,
which are detailed in the following sections, as well as
additional requirements also detailed in following sections.
3. Vertically vented heaters may be vented with either single
wall or double wall vent pipe. Follow the double wall
manufacturers clearances to combustibles.
4. All heaters come with a factory installed 3" vent adapter for
attaching the vent pipe to the heater. Attach the vent pipe to
the adapter with 3 non-corrosive screws. (Drill pilot holes
through the vent pipe and adapter prior to screwing in place)
5. Do not use any vent pipe smaller than 3". Refer to the
National Fuel Gas Code for the minimum material thickness.
6. A minimum of 12" straight pipe is recommended from the
power exhauster outlet before turns in the vent system.
Suspend horizontal runs at a minimum of 3' intervals.
7. Avoid venting through unheated spaces when possible.
When single wall pipe does pass through an unheated
space, 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 350°F. Install a tee fitting at the low point of the vent
system and provide a drip leg with a cleanout cap as
shown in Figures 6.2 and 6.3. The drip leg should be
cleaned annually.
8. Keep single wall vent pipe at least 6" from combustible
material. The minimum distance from combustible material
is based on the combustible material surface not exceeding
160°F. Clearances from the vent pipe (or top of the unit)
may be required to be greater than the minimum clearance
if heat damage (such as material distortion or discoloration)
may occur.
9. When a single wall vent passes through a combustible wall
or floor, a listed thimble must be used. When a type B
double wall vent passes through a combustible wall or floor,
follow the vent pipe manufacturers clearances to
combustibles. Refer to Figure 6.1.
10. This heater is equipped with a power exhaust system.
DO NOT use any additional power exhaust systems or vent
dampers. FAILURE TO FOLLOW THESE INSTRUCTIONS
could result in serious injury or death.
11. All vertically vented heaters are category I and must be
connected to a factory built chimney or vent complying with
a recognized standard, or a masonry (or concrete) lined
chimney with a material acceptable to the authority having
jurisdiction. Venting into an unlined masonry chimney is
not permitted. Refer to the National Fuel Gas Code for
common venting.
12. Secure all vent joints with at least 3 corrosion-resistant
screws. Use an approved vent terminal to reduce down
drafts and moisture in the vent.
13. The vent must terminate no less than 5' above the vent
connector. The top of the vertical stack should extend
above any portion of a building within a horizontal distance
of 2' (see Figure 6.2).
14. The outlet of the vent should extend as shown in Figure
6.3 and Table 6.1 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 10' 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 2' (refer to Figure 6.2).
55
Table 5.1
ANSI Unit Heater Venting Requirements
Venting
Category Description Requirements
I Negative vent pressure Follow standard
Non-condensing venting requirements.
II Negative vent pressure Condensate must
Condensing be drained.
III Positive vent pressure Vent must be gas tight.
Non-condensing
IV Positive vent pressure Vent must be liquid and
Condensing gastight. Condensate
must be drained.
INSTALLATION
WARNING
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 CAN/CGA B149.1 or .2 latest edition. Failure to
follow these instructions can result in serious injury or death.
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
CAN/CGA-B149.1 for natural gas units, and CAN/CGA-B149.2
for propane units.
Venting
