FloAire INDIRECT FIRED BENT TUBE MODULE - Manual (Page 8)

8
Indoor Flue Venting
Indoor gas fired heating equipment must be vented. Do not operate un-
vented. Gas fired heating equipment which has been improperly vented,
or which experiences a blocked vent condition may emit flue gases into
heated spaces.
General Venting Guidelines
1. Installation of venting must conform with local building codes, or
in the absence of local codes, follow the National Fuel Gas Code.
2. On Units with multiple furnaces, each furnace must be ducted to the outside using its own
isolated duct run. Ducts used on each single furnace must Not be Connected together in
any fashion. Failure to adhere to this may result in a build-up of Carbon-Monoxide in the
space when the furnace is operating with less than all of its furnaces powered.
3. Do not use a vent pipe smaller than the size of the outlet on the heater.
4. Install with a minimum upward slope from unit of ¼ inch per foot and suspend from overhead
structure at points no greater than 3 feet apart. For best venting, put as much vertical vent as
close to the unit as possible.
5. Fasten individual lengths of vent together with at least three corrosion resistant sheet metal
screws.
6. Vent pipes should be fitted with a tee with a drip leg and clean out tap at the low point in the vent
run. This should be inspected and cleaned out periodically during the heating season.
7. Do NOT use dampers or other devices in the vent or combustion air pipes.
8. Use a vent terminal to reduce downdrafts and moisture in the vent line.
9. A vent system that terminates vertically but has a horizontal run that exceeds 75% of the vertical
rise is considered horizontal.
10. Pressures in Category III venting systems are positive and therefore care must be taken to
prevent flue products from entering the heated space. Use only venting materials and
components that are UL listed and approved for Category III venting systems.
11. Vent pipes must all be sealed and gastight.
Vertically Vented Furnaces
1. Use single wall or double wall (Type B) vent pipe of a diameter listed
in the following table for the appropriate model.
2. Maximize the height of the vertical run of vent pipe. A minimum of
five (5) feet (1.5m) of vertical pipe is required. The top of the vent
pipe must extend at least two (2) feet (0.61m) above the highest point
on the roof. Use Listed Type B vent for external runs. An approved
weatherproof vent cap must be installed on the vent termination.
3. Horizontal runs should be pitched upward ¼ in. per foot (21mm/m) and should be supported at three
(3) foot (1m) maximum intervals.
4. Design vent pipe runs to minimize the use of elbows. Each 90⁰ elbow is equivalent to five (5) feet
(1.5m) of straight vent pipe.
5. Vent pipe should not be run through unheated spaces. If such runs cannot be avoided, insulate the
vent pipe to prevent condensation. Insulation should be a minimum of ½ in. (12.7mm) thick foil faced
fiberglass minimum of 1½ # density.
6. Dampers must not be used in vent piping runs, as spillage of flue gases into the occupied space
could result.
7. Vent connectors serving Category 1 heaters must not be connected into any portion of a mechanical
draft system operating under positive pressure.
National Fuel Gas Code Venting Pipe requirement
75,000-149,999
Use 5-inch pipe
150,000-400,000 Use 6-inch pipe
IMPORTANT
Furnace Only Modules must be
installed in a positive pressure
airstream. Do not install in a
duct on the suction side of a
fan.
IMPORTANT
Furnace Only Modules must be
installed in a positive pressure
airstream. Do not install in a
duct on the suction side of a
fan.