12
INSTALLATION (Continued)
3. Each unit MUST have its own vent system. It MUST
NOT be connected to other vent systems or to a
chimney.
4. Use single wall pipe constructed of 26 gauge
galvanized steel or material of equivalent durability
and corrosion resistance for the vent system. For
installation 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 current CAN/CGA-B149.1, Installation
Codes for Natural Gas Burning Appliances and
Equipment or CAN/CGA-B149.2, Installation Codes
for Propane Gas Burning Appliances and Equipment.
Never use a pipe of a diameter
other than that specifi ed in Table 1, (“D” dia. fl ue
opening)! Never use PVC/ABS or other non-
metallic pipe for venting! To do so may result in
serious damage to the unit or severe personal
injury or death!
5. Any run of single wall vent pipe passing through an
unheated space must be insulated with an insulation
suitable to 550°F.
6. The combustion and exhaust vent air systems must
be installed to prevent collection of condensate.
Pitch horizontal pipes downward 1/4 inch per foot
(21mm/m) toward the terminal caps to facilitate
drainage (see Figure 8A). Vertical vent pipes should
be arranged as depicted in Figure 8.
7. The equivalent length of the vent system must not
be less than 5 feet (1.5m) and must not exceed 50
feet (15.2m). Equivalent length is the total length of
straight sections PLUS 15 feet (4.6m) for each 90°
elbow and 5 feet (1.5m) for each 45 elbow.
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 be used
to seal each joint. General Electric RTV-108, Dow-
Corning RTV-732, or an equivalent, may be used
instead of the tape.
9. For horizontal vent systems longer than 5 feet
(1.5m), the system must be suppor ted from
overhead building structures at 3 foot (1m) intervals.
10. The exhaust vent system must remain at a minimum
of 6 inches (152mm) from all combustible materials.
Any part of the vent system that passes through a
combustible material must be properly insulated.
NOTICE: Increasing the clearance distance may be
necessary If there is a possibility of distortion or
discoloration of adjacent materials.
For a VERTICAL vent pipe section that passes through a
floor or roof, an opening 4 inches (102mm) greater in
diameter is required. The opening must be insulated and
fl ashed in accordance with applicable installation codes.
A HORIZONTAL section of an exhaust vent system that
passes through a combustible wall must be constructed
and insulated as shown in Figure 9A.
11. The top of a VERTICALLY VENTED exhaust system
must extend at least 3 feet (1m) above the roof surface
that it passes through. The point of termination for a
HORIZONTALLY VENTED exhaust system must be
at least 12 inches (305mm) from the exterior wall that
it passes through. In addition, the termination point
must be at least 3 feet (1m) above grade or above
snow line, more than 6 feet (2m) from the combustion
air inlet of another appliance, more than 3 feet (1m)
from any building opening, and more than 4 feet
(1.3m) from, and not directly above any electric meter,
gas meter, regulator, or relief equipment. See Vent/
Intake Installations in Figures 8 & 9.
Figure 8. Vertical Intake/Vent Installation
CAT-2764
*
Size according to expected snow depths.
**
If excessive condensation develops, a drip leg
with a condensate drain may be required.
Insulating pipes may eliminate the problem.
