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Details of Exhaust Piping Terminations for Non‐Direct
Vent Applications
Exhaust pipes may be routed either horizontally through an
outside wall or vertically through the roof. In attic or closet
installations, vertical termination through the roof is pre
ferred. Figures 47 through 48 show typical terminations.
1. Exhaust piping must terminate straight out or up as
shown. The termination pipe must be sized as listed in
table 17.The specified pipe size ensures proper
velocity required to move the exhaust gases away
from the building.
2. On field supplied terminations for side wall exit, ex
haust piping may extend a maximum of 12 inches
(305mm) for 2” PVC and 20 inches (508mm) for 3”
(76mm) PVC beyond the outside wall.
FIGURE 47
NON-DIRECT VENT ROOF TERMINATION KIT
(15F75 or 44J41)
UNCONDITIONED
ATTIC SPACE
3” (76mm) OR
2” (51mm) PVC
PROVIDE SUPPORT
FOR EXHAUST LINES
12” (305mm)
ABOVE AVE.
SNOW
ACCUMULATION
SIZE TERMINATION
PIPE PER TABLE
17.
1/2” (13mm) FOAM
INSULATION
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 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 mul
tiple furnaces must meet local codes.
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 48
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
EXTERIOR
PORTION OF
CHIMNEY
INSULATE
TO FORM
SEAL
SHEET
METAL TOP
PLATE
SIZE TERMINATION
PIPE PER TABLE 17.
ML195UH NON-DIRECT VENT APPLICATION
USING EXISTING CHIMNEY
Minimum 12” (305MM)
above chimney top
plate or average snow
accumulation
Condensate Piping
This unit is designed for either right‐ or left‐side exit of con
densate piping in upflow applications. In horizontal applica
tions, the condensate trap must extend below the unit. An
8” service clearance is required for the condensate trap.
Refer to figures 49 and 51 for condensate trap locations.
Figure 58 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.
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 - For furnaces with a 1/2” drain connection use a 3/8 al
len wrench and remove plug (figure 49) 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 header box. For furnaces with a 3/4”
drain connection use a large flat head screw driver or a
