Page 14
FIGURE 16
Exhaust Pipe
NOTE
− Exhaust pipe MUST be glued to furnace exhaust fittings.
NOTE −
All horizontal runs of exhaust pipe must slope back to-
ward unit. A minimum of 1/4" (6mm) drop for each 12" (305mm)
of horizontal run is mandatory for drainage.
NOTE
− Exhaust piping should be checked carefully to make
sure there are no sags or low spots.
12” ma x
of straight pip e
Exhaust Pipe
12” Min.
Horizontal
Gas Furnace
NOTE
− The exhaust collar on all models is sized to ac-
commodate 2" Schedule 40 vent pipe. In horizontal ap-
plications, any transition to exhaust pipe larger than 2"
must be made in vertical runs of the pipe. Therefore a 2"
elbow must be added before the pipe is transitioned to
any size larger than 2". This elbow must be added to the
elbow count used to determine acceptable vent lengths.
Contact the Application Department for more information
concerning sizing of vent systems which include multiple
pipe sizes.
IMPORTANT
Do not use screens or perforated metal in exhaust or
intake terminations. Doing so will cause freeze−ups
and may block the terminations.
TABLE 4
MINIMUM VENT PIPE LENGTHS
SLP98UHV
MODEL
MIN. EQUIV.
VENT
LENGTH
EXAMPLE
070, 090, 110
15 ft.*
5 ft. plus 2 elbows of 2", 2−1/2"
or 3" diameter pipe
135
5 ft. plus 2 elbows of 3"
diameter pipe
*Any approved termination may be added to the minimum equivalent length
listed.
FIGURE 17
Piping Size Process
1
2
3
4
5
6
Which style termination
being used?
Standard or concentric?
See table 3.
Which needs
most elbows?
Intake or
exhaust?
How many elbows?
Count all elbows inside
and outside house.
Desired pipe size?
2", 2−1/2", 3"
Use table 5 to find max
intake or exhaust pipe
length. Includes all vent
pipe and elbows inside
and outside the house.
What is the altitude of
the furnace installation?
7
What is the
furnace capacity?
045, 070, 090,
110 or 135?