Lennox G51MP SERIES Installation Instructions Manual page 30

3 − If exhaust piping must be run up a side wall to position
above snow accumulation or other obstructions, pip-
ing must be supported every 3 feet (.9m) as shown in
figure 22. Refer to figure 42 for proper piping method.
When exhaust piping must be run up an outside wall,
any reduction in exhaust pipe size must be done after
the final elbow.
Inches(mm)
UNCONDITIONED
SPACE
OUTSIDE WALL
PROVIDE SUPPORT
FOR EXHAUST LINES
EVERY 36" (914)
FIELD−PROVIDED
REDUCER MAY BE
REQUIRED TO
ADAPT LARGER
VENT PIPE SIZE TO
TERMINATION
1/2" (13) FOAM
INSULATION IN
UNCONDITIONED
SPACE
SIDE VIEW
NON−DIRECT VENT WALL RING TERMINATION
(15F74)
FIGURE 42
G51MP NON−DIRECT VENT APPLICATION
USING EXISTING CHIMNEY
SIZE TERMINATION
PIPE PER TABLE 8.
3" − 8"
(76mm−
203mm)
MINIMUM 12" (305mm)
ABOVE ROOF OR AV-
ERAGE SNOW ACCU-
MULATION
SHEET
METAL TOP
PLATE
INSULATE
TO FORM
SEAL
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 43
12" (305) Max. for 2" (51)
SIZE TER-
MINATION
PIPE PER
TABLE 8.
12" (305) ABOVE
AVERAGE SNOW
ACCUMULATION
1/2" (13) FOAM
INSULATION
STRAIGHT−CUT OR
ANGLE−CUT IN DIRECTION
OF ROOF SLOPE
EXHAUST VENT
1/2" (13mm)
WEATHERPROOF
INSULATION
SHOULDER OF FITTINGS
PROVIDE SUPPORT
OF PIPE ON TOP PLATE
3" − 8"
(76mm−
203mm)
EXTERIOR
PORTION OF
CHIMNEY
Condensate Piping
This unit is designed for either right- or left-side exit of con-
densate piping in either upflow or downflow applications;
however, it must be installed on the same side of the unit as
the exhaust piping. In horizontal applications, the conden-
sate trap should extend below the unit. A 5−1/2" service
clearance is required for the condensate trap. Refer to fig-
ure for condensate trap locations.
CONDENSATE TRAP LOCATIONS
(Unit shown in upflow position)
Horizontal
left and
optional
downflow
Optional
upflow
NOTE − In upflow applications where side return
air filter is installed on same side as the conden-
sate trap, filter rack must be installed beyond
condensate trap to avoid interference.
1 − Determine which side condensate piping will exit the
unit. Remove plugs from the condensate collar at the
appropriate location on the side of the unit.
NOTE − The condensate trap is factory−shipped with
two rubber O−rings and two rubber clean−out caps
installed. Check to make sure that these items are in
place before installing the trap assembly.
2 − Install condensate trap onto the condensate collar.
Use provided HI/LO screws to secure two upper
flanges of the trap to the collar. Use provided sheet
metal screw to secure bottom trap flange to side of
unit. DO NOT apply glue to secure condensate trap
to cabinet. All other joints must be glued. See figure
45.
NOTE − In upflow and downflow applications, con-
densate trap must be installed on the same side as
exhaust piping.
Page 30
Horizontal
right and
optional
downflow
Optional
upflow
FIGURE 44