20
VENTING (continued)
NOTICE: Combustion and exhaust venting instructions below describe two-pipe venting of a duct furnace
confi gured for separated combustion. If converting the duct furnace to separated combustion, an Air Inlet
Kit (X9) is required and instructions included with the kit must be followed to complete the conversion
process. If venting a separated combustion duct furnace concentrically (through one roof or wall termination),
a Combustion Air Inlet Kit (X8) is required and instructions included with the kit should be followed with
regards to vent pipe installation. Both kits are available from the manufacturer.
COMBUSTION AIR VENTING AND PIPING
Never operate separated combustion
duct furnaces without combustion air and fl ue gas
piping in place or severe personal injury or death
may occur!
CARBON MONOXIDE! Your venting
system must not be blocked by any snow, snow
drifts, or any foreign matter. Inspect your venting
system to ensure adequate ventilation exists at all
times! Failure to heed these warnings could result
in Carbon Monoxide Poisoning (symptoms include
grogginess, lethargy, inappropriate tiredness, or
fl u-like symptoms).
1. In the United States, the combustion air system
installation must be in accordance with the latest
edition of ANSI Z223.1 (NFPA 54) National Fuel Gas
Code. In Canada, installation must be in accordance
with CSA-B149.1 “Installation Code for Natural Gas
Burning Appliances and Equipment” and CSA-B149.2
“Installation Code for Propane Burning Appliances
and Equipment.”
2. A Breidert Type L or Fields Starkap, furnished by the
customer, must be installed at the termination point
of the combustion air system. See Figures 9A and
9B.
3. Each duct furnace MUST have its own combustion
air system. It MUST NOT be connected to other air
intake systems.
4. Use UL 1738 listed single wall pipe for the vent
system. For installations in Canada, use UL S636
listed vent pipe conforming with local building codes,
or in the absence of local building codes, with current
CSA-B149.1 “Installation Codes for Natural Gas
Burning Appliances and Equipment” or CSA-B149.2,
“Installation Codes for Propane Gas Burning
Appliances and Equipment.”
Never use pipe of a diameter other
than that specifi ed in Table 1! Never use PVC, ABS
or any other non-metallic pipe for venting! To do
so may result in serious damage to the unit and/
or severe personal injury or death!
5. Long runs of single wall combustion air piping passing
through an unheated space may require insulating if
condensation becomes noticeable.
6. The combustion air system must be installed to
prevent collection of condensate. Pitch horizontal
pipes downward 1/4 inch per foot (21mm/m) toward
the inlet cap to facilitate drainage. Vertical combustion
air pipes should be piped as depicted in Figure 9A.
7. The equivalent length of the combustion air system
must not be less than 5 feet (1.5m) and must not
exceed 50 feet (15.2m). Equivalent length equals the
total length of straight pipe, plus 10 feet (3.05m) for
each 90° elbow and 4 feet (1.22m) for each 45° elbow.
NOTICE: For optimum performance keep the
combustion air system as straight as possible.
8. Each slip joint must be secured with at least three
corrosion resistant screws. Two full turns of 3M #425
Aluminum Foil Tape or its equivalent must then be
used to seal each joint. General Electric RTV-108,
Dow-Corning RTV-732 or an equivalent may be used
instead of tape.
9. For horizontal combustion air systems longer than
5 feet (1.5m), the system must be supported from
overheard building structures at 4 feet (1.22m)
maximum intervals in the United States and at 3 feet
(1m) maximum intervals in Canada.
