InsTAllATIon - venTIng
jurisdiction type B vent may be used for the last section
of vent pipe to maintain clearance to combustibles while
passing through wall or floor. See Figure 6.1. Any material
used to close the opening must be noncombustible.
A11. All seams and joints of the single wall pipe must be sealed
with metallic tape or silastic suitable for temperatures up to
400°F. Wrap the tape two full turns around the vent pipe.
One continuous section of double wall vent pipe may be
used within the vent system. Refer to instruction A12 in
"Section A – General Instructions – All Units" for attaching
double wall pipe to single wall pipe.
A12. The following are General Instructions for Double Wall
(Type B) Terminal Pipe Installation:
How to attach a single wall vent terminal to double wall
(type B) vent pipe:
1. Look for the "flow" arrow on the vent pipe.
2. Slide the vent terminal inside the exhaust end of the
double wall vent pipe.
3. Drill (3) holes through the pipe and the vent terminal.
Using 3/4" long sheet metal screws, attach the cap to
the pipe. Do not over tighten.
How to connect a single wall vent system to a double
wall (type B) vent pipe:
1. Slide the single wall pipe inside the inner wall of the
double wall pipe.
2. Drill (3) holes through both walls of the single and
double wall vent pipes. Using 3/4" sheet metal screws,
attach the two pieces of pipe. Do not over tighten.
3. The gap between the single and double wall pipe must
be sealed but it is not necessary to fill the full volume
of the annular area. To seal, run a large bead of 400°F
silastic around the gap.
A13. Vent termination clearances must be maintained:
Table 7.1 - vent Termination Clearances
structure
Forced air inlet within 10 feet
Combustion air inlet of another
appliance
Door, window, gravity air inlet,
or any building opening
Electric meter, gas meter, gas
regulator, and relief equipment ➀
Gas regulator ➀
Adjoining building or parapet wall
Adjacent public walkways
Grade (ground level)
➀ Do not terminate the vent directly above a gas meter or regulator.
➁ The vent must be at least 6" higher than anticipated snow depth.
A14. Do NOT vent this appliance into a masonry chimney.
A15. Do NOT use dampers or other devices in the vent or
combustion air pipes.
A16. The venting system must be exclusive to a single
appliance, and no other appliance is allowed to be vented
into it.
A17. Precautions must be taken to prevent degradation of
building materials by flue products.
A18. Single wall vent pipe must not pass through any
unoccupied attic, inside wall, concealed space, or floor.
A19. Uninsulated single wall vent pipe must not be used
outdoors for venting appliances in regions where the 99%
winter design temperature is below 32°F.
minimum Clearances for
vent Terminal location
3 feet above
6 feet all directions
4 feet horizontal and below
1 foot above
4 feet horizontal (U.S.)
6 feet horizontal (Canada)
3 feet horizontal (U.S.)
6 feet horizontal (Canada)
6 feet all directions
7 feet all directions
3 feet above ➁
6-584.2
A20. Long runs of horizontal or vertical combustion air pipes
may require insulation in very cold climates to prevent the
buildup of condensation on the outside of the pipe where
the pipe passes through conditioned spaces.
A21. Vertical combustion air pipes should be fitted with a tee
with a drip leg and a clean out cap to prevent against the
possibility of any moisture in the combustion air pipe from
entering the unit. The drip leg should be inspected and
cleaned out periodically during the heating season.
A22. In addition to following these General Instructions, specific
instructions for Vertical and Horizontal vent systems in
2-Pipe or Concentric Vent configurations must also be
followed. The following outlines the differences:
vertical vent system determination
•
Vertical vent systems terminate vertically (up) (an example is
shown in Figure 8.1).
•
Determine the venting configuration as follows:
> For two building penetrations through the wall or roof (one
for the combustion air inlet pipe and one for the vent pipe),
proceed to "Section B - Vertical 2-Pipe Venting".
> For a single larger building penetration through the wall or
roof, through which both the combustion air inlet and vent
pipes will pass, proceed to "Section D - Horizontal and
Vertical Concentric Venting".
> For all other cases, proceed to the next section for
Horizontal Vent System Determination.
Horizontal vent system determination
•
Horizontal vent systems terminate horizontally (sideways)
(an example is shown in Figure 9.1).
•
Determine the venting configuration as follows:
> For two building penetrations through the wall or roof (one
for the combustion air inlet pipe and one for the vent pipe),
proceed to "Section C - Horizontal 2-Pipe Venting".
> For a single larger building penetration through the wall or
roof, through which both the combustion air inlet and vent
pipes will pass, proceed to "Section D - Horizontal and
Vertical Concentric Venting".
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