38151-4-0320
Page 9
VENTING GUIDELINES
The installer must consider all of the following venting rules.
•
Flue pipe MUST always have an upward slope (1/4 inch per
foot minimum).
•
Flue pipe MUST run as directly as possible and have as few
elbows as possible.
•
Flue pipe MUST be as large as the flue collar on the draft diverter.
•
The flue pipe MUST be on the outside of the draft diverter collar.
•
The flue pipe MUST be sealed. No open “Tees.”
•
The flue pipe’s vertical rise MUST always be at least twice the
length of the horizontal run.
•
Each new piece of flue pipe that is connected when getting
farther away from the furnace MUST connect on the outside
of the previous one. Remember, the exhaust must flow “
into
”
the next pipe.
•
For flue pipe running through walls, roof and within one inch
of combustible construction, use B-1 (one inch clearance to
combustibles) vent pipe. Any combustible material that is within
2 inches of the vent connection or the draft diverter must be
shielded with a non-combustible material.
•
When connecting the flue pipe to the chimney, the pipe MUST
go fully in and be cemented. The flue pipe MUST NOT go too
far into the chimney. It should be cut off as it will interfere with
normal venting.
•
Flue pipe MUST NOT have any downward sloping sections,
dips or sags.
•
Do not use Type C single wall flue pipe.
Uninsulated single-
wall metal pipe shall not be used outdoors in cold climates
for venting gas utilization equipment.
•
The flue pipe MUST NOT be connected to a chimney that has
a fireplace connected to it.
Helpful Hints
1. If you have a choice, select a location close to the chimney.
2. If there is no chimney, you will have to run a flue pipe from
the furnace, up to and above the house roof. Select a location
permitting the most direct run. Try going up to the roof through
a closet. Remember that the flue pipe must slope upwards at
least 1/4 of an inch for each foot and you may find floor joists
in your path, so it is important to plan the run carefully.
3. If you have decided to go up to the roof through a closet, re-
member that you MUST keep a minimum distance of 1 inch
between Type B vent pipe and any combustible material. Run
it through a single wall pipe that is 2 inches larger in diameter
than the flue pipe. Use thimbles when going through floor and
ceiling and flashing when going through roof.
ROOF
LINE
ROOF
LINE
ROOF
LINE
ROOF
LINE