Lennox International Inc MERIT SERIES GAS FURNACE DOWNFLOW AIR DISCHARGE, ML193DF

	12" (305mm) MAX. for 2" (51mm)
UNCONDITIONED	20" (508mm) MAX. for 3" (76mm)
SPACE
6" (152mm)
Max	SIZE TER-
	MINATION
*WALL SUPPORT	PIPE PER
OUTSIDE WALL	TABLE 8.
FIELD−PROVIDED	12" (305mm)
REDUCER MAY BE
	ABOVE GRADE OR
REQUIRED TO
	AVERAGE SNOW
ADAPT LARGER
	ACCUMULATION
VENT PIPE SIZE TO
TERMINATION

1/2" (13mm) FOAM
INSULATION IN
UNCONDITIONED	1/2" (13mm) FOAM
SPACE
	INSULATION
*Use wall support every 24" (610). Use
two supports if extension is greater
than 24" but less than 48".

NON−DIRECT VENT FIELD SUPPLIED WALL TERMINATION EX- TENDED OR (15F74) WALL TERMINATION VENT PIPE EXTENDED

FIGURE 40

ML193DF NON−DIRECT VENT APPLICATION

USING EXISTING CHIMNEY

	SIZE TERMINATION							STRAIGHT−CUT OR
	PIPE PER TABLE 8.						ANGLE−CUT IN DIRECTION
								OF ROOF SLOPE
				3" − 8"
							EXHAUST VENT
				(76mm−			1/2" (13mm)
				203mm)
							WEATHERPROOF
Minimum 12" (305MM)
							INSULATION
above chimney top
plate or average snow
					SHOULDER OF FITTINGS
accumulation
						PROVIDE SUPPORT
					OF PIPE ON TOP PLATE
			SHEET
			METAL TOP
			PLATE
						3" − 8"
						(76mm−
						203mm)
		INSULATE
		TO FORM						EXTERIOR
		SEAL						PORTION OF
								CHIMNEY

NOTE − Do not discharge exhaust gases directly into any chimney or vent stack. If ver- tical discharge through an existing unused chimney or stack is required, insert piping inside chimney until the pipe open end is above top of chimney and terminate as illus- trated. In any exterior portion of chimney, the exhaust vent must be insulated.

FIGURE 41

Condensate Piping

This unit is designed for either right- or left-side exit of con- densate piping. Refer to figure 42 for condensate trap loca- tions.

NOTE − If necessary the condensate trap may be installed up to 5´ away from the furnace. Use PVC pipe to connect trap to furnace condensate outlet. Piping from furnace must slope down a minimum of 1/4" per ft. toward trap.

CONDENSATE TRAP AND PLUG LOCATIONS
Trap
(same on
right side)
1−1/2 in.	Plug
	(same on left
	side)

FIGURE 42

1 − Determine which side condensate piping will exit the unit, location of trap, field−provided fittings and length of PVC pipe required to reach available drain.

2 − Remove plug (figure 42) from the cold end header box at the appropriate location on the side of the unit. Install field−provided 1/2" NPT male fitting into cold end head- er box. Use teflon tape or appropriate pipe dope.

3 − Install the cap over the clean out opening at the base of the trap. See figure 45.

NOTE − Vinyl tubing may be used for condensate drain. Tubing must be 1−1/4" OD X 1" ID and should be attached to the drain on the trap using a hose clamp.

4 − Install drain trap using appropriate PVC fittings, glue all joints. Glue the provided drain trap as shown in fig- ure 45. Route the condensate line to an open drain.

NOTE − If necessary the condensate trap may be installed up to 5 feet away from the furnace. Piping from furnace must slope down a minimum of 1/4" per ft. toward trap.

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