15
VENTING – GENERAL GUIDELINES
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
flu-like symptoms).
Each unit must have an individual vent pipe and vent
terminal! Each unit MUST NOT be connected to other
vent systems or to a chimney.
Do not damper or add heat recovery devices to the flue piping.
Failure to open such a damper prior to operating gas unit will
result in the spillage of flue gas into the occupied space.
NOTICE: The high efficiency unit heater is likely
to produce a vapor plume due to condensation.
Surfaces near the vent termination will likely become
coated with condensation.
Condensing flue gases can freeze
on exterior building surfaces which may cause
discoloration and degradation of the surfaces.
ANSI now organizes vented
appliances into four categories.
Venting Categories
Non-
Condensing
Condensing
Negative
Vent
I
II
Pressure
Positive
Vent
III IV
Pressure
Category I
Includes non-condensing appliances
with negative vent pressure, like the
traditional atmospheric unit heater.
Category II
Groups condensing appliances
with negative vent pressure.
Category III
Appliances are non-condensing and
operate with a positive vent pressure.
Category IV
Covers condensing appliances with
positive vent pressure.
NOTICE: Category I, II and III do
not apply to equipment specified
within this manual. These unit
heaters are Category IV appliances.
All unit heaters must be vented! All Venting installations shall be in accordance with the latest edition of Part 7, Venting
of Equipment of the National Fuel Gas Code, ANSI Z223.1 (NFPA 54), or applicable provisions of local building codes.
The following instructions apply to Canadian installations in addition to installation and operating instructions:
1. Installation must conform with local building codes, or in the absence of local 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.
2. Any reference to U.S. standards or codes in these instructions are to be ignored, and the applicable Canadian
standards or codes applied.
Vent Systems Termination Clearance Requirements
Structure/Object
Minimum Clearance for Termination Locations
USA
CANADA
Door, window, or gravity vent inlet;
combustion air inlet for other appliances
9 in. for 10,000 to 50,000 BTU/Hr input; 12 in. for input
exceeding 50,000 BTU/Hr.
9 in. (230mm) for 10,000 to 50,000 BTU/Hr input; 12 in.
(305mm) for input exceeding 50,000 BTU/Hr.
Forced air inlet within 10 ft.
3 ft. above
6 ft. (1.8m)
Adjoining Building or parapet
10 ft.
10 ft. (3.04m)
Adjacent public walkways
7 ft. above
grade
7 ft. (2.1m) above grade
Electric, gas meters & regulators
4 ft. horizontal
3 ft. (0.9m) horizontally from meter/regulator assembly. 6 ft.
(1.8m), any direction, from a gas service regulator vent outlet
Above grade level*
1 ft.
1 ft. (0.3m)
*Minimum above maximum snow depth, or per local code, whichever is greater.
Table 4
FLUE PIPE REDUCER
Size 200 units ship with a field installed 2" to 3" PVC
reducer and size 300 units ship with a field installed
2" to 4" PVC reducer. The reducer must be installed
in a horizontal section of the flue pipe system within
12 inches (305 mm) of the unit. All vent pipe joints and
seams must be sealed to prevent leakage. All joints
must be cleaned prior to assembly. Joints should then be
primed in accordance with ASTM F 656. After priming,
joints should be cemented per ASTM D 2564.
Size 400 units ship with a field installed 2" to 4" PVC
drain tee fitting. The drain tee must be installed in a
horizontal section of the flue pipe system within 12
inches (305 mm) of the unit with the drain pointing
downward. The condensate tubing will ship connected
to the flue collector coiled inside the power venter
compartment. The tubing should be uncoiled and
connected to the bottom of the condensate drain tee. All
vent pipe joints and seams must be sealed to prevent
leakage. All joints must be cleaned prior to assembly.
Joints should then be primed in accordance with ASTM F
656. After priming, joints should be cemented per ASTM
D 2564.
