Vent Pipe Guidleines - Lennox ELITE Series Installation Instructions Manual

Vent Piping Guidelines
NOTE - Lennox has approved the use of DuraVent
Centrotherm manufactured vent pipe and terminations
as an option to PVC. When using the PolyPro® by Du-
raVent or InnoFlue® by Centrotherm venting system the
vent pipe requirements stated in the unit installation in-
struction – minimum & maximum vent lengths, termination
clearances, etc. – apply and must be followed. Follow the
instructions provided with PoyPro by DuraVent and Inno-
Flue by Centrotherm venting system for assembly or if re-
quirements are more restrictive. The PolyPro by Duravent
and InnoFlue by Centrotherm venting system must also
follow the uninsulated and unconditioned space criteria
listed in table 8.
The EL296DFE can be installed as either a Non-Direct
Vent or a Direct Vent gas central furnace.
NOTE - In Non-Direct Vent installations, combustion air is
taken from indoors or ventilated attic or crawlspace and
flue gases are discharged outdoors. In Direct Vent instal-
lations, combustion air is taken from outdoors and flue
gases are discharged outdoors.
Intake and exhaust pipe sizing -- Size pipe according
to TABLE 6 and TABLE 7. Count all elbows inside and
outside the home. TABLE 6 lists the minimum vent pipe
lengths permitted. TABLE 7 lists the maximum pipe
lengths permitted.
TABLE 6
MINIMUM VENT PIPE LENGTHS
EL296DFE MODEL
045, 070, 090, 110
*Any approved termination may be added to the minimum length listed.
Two 45 degree elbows are equivalent to one 90 degree elbow.
Regardless of the diameter of pipe used, the standard roof
and wall terminations described in section Exhaust Piping
Terminations should be used. Exhaust vent termination
pipe is sized to optimize the velocity of the exhaust gas as
it exits the termination. Refer to TABLE 10.
In some applications which permit the use of several dif-
ferent sizes of vent pipe, a combination vent pipe may be
used. Contact Lennox' Application Department for assis-
tance in sizing vent pipe in these applications.
IMPORTANT
Do not use screens or perforated metal in exhaust or
intake terminations. Doing so will cause freeze-ups and
may block the terminations.
NOTE - It is acceptable to use any pipe size which fits
within the guidelines allowed in TABLE 7.
NOTE - All horizontal runs of exhaust pipe must slope
back toward unit. A minimum of 1/4" (6mm) drop for each
12" (305mm) of horizontal run is mandatory for drainage.
and
®
MIN. VENT LENGTH*
15 ft or 5ft plus 2 elbows or
10 ft plus 1 elbow
NOTE - Exhaust pipe MUST be glued to furnace exhaust
fittings.
NOTE - Exhaust piping should be checked carefully to
make sure there are no sags or low spots.
NOTE - If right side venting option is used, you must in-
clude the elbow at the furnace in the elbow count. If tran-
sitioning to 3" dia pipe, this elbow equates to 20' of equiv-
alent vent length for all models.
Use the following steps to correctly size vent pipe diam-
eter.
1
Which style termination
2
Standard or concentric?
3
How many elbows?
Count all elbows inside
4
and outside house.
5
What is the altitude of
6
the furnace installation?
Use table 7 or 9 to find
max intake or exhaust pipe
7
length. Includes all vent
pipe and elbows inside
and outside the house.
NOTE - Lennox offers a glueless vent adapter kit 17H92
as an option for exhaust exiting at the furnace top cap
coupling.
Page 18
What is the
furnace capacity?
045, 070, 090,
110 or 135?
being used?
See table 5.
Which needs
most elbows?
Intake or
exhaust?
Desired pipe size?
2", 2-1/2", 3"
FIGURE 26