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This appliance uses a positive
pressure venting system. All joints must be
sealed completely to prevent leakage of flue
products into occupied spaces. Failure to do this
may result in severe personal injury, death or
major property damage.
1. Vertical venting arrangements are designed to be
used with schedule 40 vent pipe. All heaters should
be vented with UL 1738 listed vent pipe. For
installations in Canada, use corrosion resistant and
gas-tight, listed vent pipe conforming with local
building codes, or in the absence of local building
codes, with the 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.
Approved vent pipe includes but is not limited to:
ULC-S636 PVC or CPVC Vent pipe. Vent pipe must
be rated for up to 140°F (60°C) operating temperature.
Type B vent should not be used.
Do not use Type B (double wall)
vent internally within the building on high
efficiency unit heaters! This can result in death,
serious injury or substantial property damage.
Use of cellular core pipe for any
exhaust vent component is prohibited. Use of
cellular core pipe may result in severe personal
injury, death, or major property damage.
NOTICE: Installations in Canada require compliance
with ULC-S636 Standard for Type BH Gas Venting
Systems
2. The vent pipe diameter MUST be as specified (see
Table 1). All unit sizes are factory equipped with
the required flue size collar; attach in place (if not
already factory-mounted to outlet).
3. The top of the vent pipe should extend at least 2 feet
(0.61 m) above the highest point on the roof within
10 feet (3.05 m) of the termination. Consideration
should be made for anticipated snow depth.
4. Vent system terminations for these appliances shall
NOT terminate in an area where the condensate
or vapor could create a nuisance or hazard or
could be detrimental to the operation of regulators,
relief valves, or other equipment. See Table 4 for
termination clearance requirements.
5. The vent pipe equivalent length must not exceed
50 feet (15.2 m). Equivalent length is total length
of straight sections PLUS 5 feet (1.5 m) for each
90 degree elbow and 2.5 feet (0.76 m) for each 45
degree elbow.
6. Seal all vent pipe joints and seams 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. The vent system must
be installed to prevent collection of condensate.
Pitch horizontal pipes downward 1/4 inch per foot
(21 mm/m) toward the unit for condensate drainage.
7. Horizontal portions of the venting systems shall be
supported at maximum intervals of 4 feet (1.2 m) to
prevent sagging (in Canada, support at 3 feet (1 m)
maximum intervals).
8. Insulate single wall vent pipe exposed to cold air or
running through unheated areas.
9. Each unit must have an individual vent pipe and
termination. Each unit MUST NOT be connected to
other vent systems or to a chimney.
Figure 9 – Vertical Venting, Standard Combustion
STANDARD COMBUSTION – VERTICALLY VENTED UNIT HEATERS
(CATEGORY IV)
CAT-10068A
FLUE PIPE
ROOF
FLASHING
