Lennox MERIT ML195UH Installation Instructions Manual page 30

2 - On field supplied terminations for side wall exit,
exhaust piping may extend a maximum of 12 inches
(305mm) for 2" PVC and 20 inches (508mm) for 3"
(76mm) PVC beyond the outside wall.
12" (305mm)
ABOVE AVE.
SNOW
ACCUMULATION
3" (76mm) OR
2" (51mm) PVC
PROVIDE SUPPORT
FOR EXHAUST LINES
NON-DIRECT VENT ROOF TERMINATION KIT
(15F75 or 44J41)
FIGURE 42
3 - If exhaust piping must be run up a side wall
to position above snow accumulation or other
obstructions, piping must be supported every 24
inches (610mm). When exhaust piping must be run
up an outside wall, any reduction in exhaust pipe
size must be done after the final elbow.
4 - Distance between exhaust pipe terminations on
multiple furnaces must meet local codes.
NON-DIRECT VENT APPLICATION
USING EXISTING CHIMNEY
Minimum 12" (305MM)
above chimney top
plate or average snow
accumulation
SHEET
METAL TOP
PLATE
INSULATE
TO FORM
SEAL
NOTE - Do
tical discharge through an existing unused chimney or stack is required, insert piping
inside
trated. In any exterior portion of chimney, the exhaust vent must be insulated.
FIGURE 43
Crawl Space and Extended Horizontal Venting
Lennox provides kit 51W18 (USA) and kit 15Z70 (Cana-
da) to install 2" or 3" PVC exhaust piping through the floor
joists and into the the crawl space. See figure 44.This kit
can also be used as a supplemental drain for installations
with condensate run back in the vent pipe (ie. long hori-
zontal runs, unconditioned spaces, etc.).
UNCONDITIONED
ATTIC SPACE
STRAIGHT-CUT OR
ANGLE-CUT IN DIRECTION
OF ROOF SLOPE
SHOULDER OF FITTINGS
PROVIDE SUPPORT
OF PIPE ON TOP PLATE
EXTERIOR
PORTION OF
CHIMNEY
Venting In A Crawl Space
Basement Floor
Condensate Piping
This unit is designed for either right-or left-side exit of con-
densate piping in upflow applications. In horizontal appli-
cations, the condensate trap must extend below the unit.
An 8" service clearance is required for the condensate
trap. Refer to figures 45 and 46 for condensate trap loca-
tions. Figure 53 shows trap assembly using 1/2" PVC or
3/4" PVC.
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.
NOTE - Appropriately sized tubing and barbed fitting may
be used for condensate drain. Attach to the drain on the
trap using a hose clamp. See figure 47.
NOTE - Do not remove the rubber grommet used to seal
the cabinet on the side not used when installing the con-
densate trap.
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 - Use a large flat head screw driver or a 1/2" drive
socket extension and remove plug (figure 45) from
the cold end header box at the appropriate location
on the side of the unit. Install provided 3/4 NPT
street elbow fitting into cold end header box. Use
Teflon tape or appropriate pipe dope. Cold end
header box drain plugs are factory installed. Check
the unused plug for tightness to prevent leakage.
Page 30
KIT 51W81
(USA)
KIT 51W81
(CANADA)
FIGURE 44