Vent Piping Guidelines - Lennox EL195UHE Unit Information

Vent Piping Guidelines

The EL195UHE 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 and flue gases are discharged outdoors.
In Direct Vent installations, combustion air is taken from out-
doors and flue gases are discharged outdoors.
Intake and exhaust pipe sizing −− Size pipe according to
tables 10 and . Table 10 lists the minimum vent pipe
11
lengths permitted. Table
11
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 14.
In some applications which permit the use of several differ-
ent 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.
Exhaust Pipe
12" max
of straight pipe
Horizontal Application
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 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.
FIGURE 19
TABLE 10
MINIMUM VENT PIPE LENGTHS
EL195UHE
MODEL
045, 070, 090, 110, 135
*Any approved termination may be added to the minimum length listed.
lists the maximum pipe lengths
12" Min.
MIN. VENT LENGTH*
15 ft. or
5 ft. plus 2 elbows or
10 ft. plus 1 elbow
Use the following steps to correctly size vent pipe diameter.
1
Furnace capacity?
Which termination?
2
Which needs
3
most elbows?
How many?
4
Desired pipe size?
5
Is the intake air
taken from a
6
vetilated attic or
crawl space?
NO
Use table 11 to find
7
max intake or
exhaust pipe length
for all altitudes.
Do not use screens or perforated metal in exhaust or
intake terminations. Doing so will cause freeze−ups
and may block the terminations.
Page 22
045, 070,
090, 110
or 135 btuh
Standard or
Concentric?
See table 9
Intake or
exhaust
2", 2 1/2"
or 3"
Use table 12 to find
YES
max pipe length for
all altitudes
(exhaust pipe only)
FIGURE 20
IMPORTANT