...Continued from page 7.
We do not recommend doing so, but if you must vent into a masonry chimney, use the following instructions.
FIG. 7A
If the floor furnace is vented into a masonry chimney, the chimney must be inspected to determine that it is clear and free of
obstructions and that it is safe for the intended use. The inside ofthe chimney must be at least 6 inches in diameter or 6 inches
by 6 inches if rectangular. Insert the vent pipe into the chimney through a masonry or noncombustible corrosion-resistant thimble
of the correct diameter. Do not push the pipe farther than 1/4 inch into the inside of the chimney. See Figure 7A. Pushing the pipe
farther into the inside of the chimney may cause partial or complete blockage as illustrated in Figure 7B.
Even following these instructions you may still have a venting problem because of the larger area to be heated inside the
chimney. This could cause pilot outage, odors coming from the furnace, or noise due to excessive heat not being vented out of
the combustion chamber. If you experience any of these problems, we recommend running the proper size "B" type vent pipe
down the chimney and connecting to the horizontal run of vent pipe with a 90-degree elbow inside the chimney. See Fig. 7C.
Extend the vent system at least 3 feet above the point where it exits the roof and at least two feet higher than any part of the roof
system within 10 feet. Terminate with a listed or approved cap. See Figure 8.
FIG. 8
MORE THAN 10'
RIDGE
1017826-A
CONNECTING THE VENT
FIG. 7B
SAFE
1/4"
10'
2' MIN.
CHIMNEY
OR METAL
PIPE:
3' MIN.
UNSAFE
RIDGE
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FIG. 7C
RECOMMENDED
10' OR
LESS
2' MIN.
CHIMNEY
OR METAL
PIPE:
3' MIN.