Lennox EL195UHNE Series Manual page 20

Vent Piping Guidelines
NOTE - Lennox has approved the use of DuraVent® and
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 14.
The EL195UHNE can be installed as either a Non-Di-
rect Vent or a Direct Vent gas central furnace.
NOTE - In Non-Direct Vent installations, combustion air
is taken from indoors and flue gases are discharged out-
doors. In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged outdoors.
Intake and exhaust pipe sizing -- Size pipe according to
tables 11 and 12. Count all elbows in side and outside the
home. Table 11 lists the minimum vent pipe lengths per-
mitted. Table 12 lists the maximum pipe lengths permitted.
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 15.
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.
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.
Horizontal Installation Offset Requirements
Exhaust Pipe
12" Max.
Horizontal
Gas Furnace
NOTE -
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.
FIGURE 21
12" Min.
Page 20
TABLE 11
MINIMUM VENT PIPE LENGTHS
EL195UH Model
040, -060, -080, 100
*Any approved termination may be added to the minimum
length listed. Two 45 degree elbows are equivalent to one 90
degree elbow.
Piping Size Process
What is the
1
furnace capacity?
Which style termination
being used?
2
Standard or concentric?
Which needs
most elbows?
3
Intake or
exhaust?
How many elbows?
Count all elbows inside
4
and outside house.
Desired pipe size?
5
What is the altitude of
6
the furnace installation?
determine
max intake or exhaust pipe
7
length. Includes all vent
pipe and elbows inside
and outside the house.
FIGURE 22
IMPORTANT
Do not use screens or perforated metal in exhaust
or intake terminations. Doing so will cause freeze-
ups and may block the terminations.
MIN. VENT LENGTH*
15 ft. or 5 ft. plus 2 elbows
or 10 ft. plus 1 elbow