Lennox International Inc EL296UHE Vent Piping Guidelines, Exhaust Piping Figures 22, 24

Resize the common venting system to the minimum vent pipe size determined by using the appropriate tables in Appendix G. (These are in the current stan­ dards of the National Fuel Gas Code ANSI Z223.1.

CHIMNEY	REPLACING FURNACE THAT
OR GAS	WAS PART OF A COMMON
VENT	VENT SYSTEM
(Check sizing
for water
heater only)

FURNACE	WATER
(Replaced	HEATER
by EL296)
	OPENINGS
	(To Adjacent
	Room)

If an EL296UHE furnace replaces a furnace which was commonly vented with another gas appliance, the size of the existing vent pipe for that gas ap­ pliance must be checked. Without the heat of the original furnace flue products, the existing vent pipe is probably oversized for the single water heater or other appliance. The vent should be checked for proper draw with the remaining appliance.

FIGURE 21

Exhaust Piping (Figures 22, 24 and 25)

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

The EL296UHE 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 tables 3 and 5. Count all elbows inside and outside the home. Table 3 lists the minimum vent pipe lengths per­ mitted. Table 5 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 8.

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.

Horizontal Installation Offset Requirements

Exhaust Pipe

12” Max. 12” Min.

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 22

TABLE 3

MINIMUM VENT PIPE LENGTHS

EL296UHE	MIN. VENT LENGTH*
MODEL
	15 ft. or
045, 070, 090, 110, 135	5 ft. plus 2 elbows or
	10 ft. plus 1 elbow

*Any approved termination may be added to the minimum length listed.

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