Lennox EL296UHVX Series Unit Information page 53

Resize the common venting system to the minimum
vent pipe size determined by using the appropriate ta­
bles in Appendix G. (These are in the current stan­
dards of the National Fuel Gas Code ANSI Z223.1.
CHIMNEY
OR GAS
VENT
(Check sizing
for water
heater only)
FURNACE
(Replaced
by EL296)
If an EL296UHV furnace replaces a furnace which was commonly
vented with another gas appliance, the size of the existing vent pipe
for that gas appliance must be checked. Without the heat of the orig­
inal furnace flue products, the existing vent pipe is probably over­
sized for the single water heater or other appliance. The vent should
be checked for proper draw with the remaining appliance.
FIGURE 19
Exhaust Piping (Figures 20, 22 and 23)
Route piping to outside of structure. Continue with installa­
tion following instructions given in piping termination sec­
tion.
CAUTION
Do not discharge exhaust into an existing stack or
stack that also serves another gas appliance. If verti­
cal discharge through an existing unused stack is re­
quired, insert PVC pipe inside the stack until the end
is even with the top or outlet end of the metal stack.
CAUTION
The exhaust vent pipe operates under positive pres­
sure and must be completely sealed to prevent leak­
age of combustion products into the living space.
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
®
InnoFlue by Centrotherm venting system the vent pipe re­
quirements stated in the unit installation instruction – mini­
mum & maximum vent lengths, termination clearances,
etc. – apply and must be followed. Follow the instructions
provided with PoyPro by DuraVent and InnoFlue by Cen­
trotherm venting system for assembly or if requirements
are more restrictive. The PolyPro by Duravent and In­
noFlue by Centrotherm venting system must also follow
the uninsulated and unconditioned space criteria listed in
table 26.
REPLACING FURNACE THAT
WAS PART OF A COMMON
VENT SYSTEM
WATER
HEATER
OPENINGS
(To Adjacent
Room)
®
and
®
by DuraVent or
Page 53
The EL296UHV 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 installations,
combustion air is taken from outdoors and flue gases are
discharged outdoors.
Intake and exhaust pipe sizing -- Size pipe according to ta­
bles 23 and 24. Count all elbows inside and outside the
home. Table 23 lists the minimum vent pipe lengths permit­
ted. Table 24 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 27.
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 appli­
cations, 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. Con­
tact 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 - 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 20
TABLE 23
MINIMUM VENT PIPE LENGTHS
EL296UHV
MODEL
045, 070, 090, 110, 135
*Any approved termination may be added to the minimum length listed.
12" Min.
MIN. VENT LENGTH*
15 ft. or
5 ft. plus 2 elbows or
10 ft. plus 1 elbow