Page 49
SLP98 DIRECT VENT APPLICATION
USING EXISTING 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 37
8” - 12”
(203mm - 305mm)
3” - 8”
(76mm-
203mm)
3” - 8”
(76mm-
203mm)
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
ALTERNATE
INTAKE PIPE
INTAKE PIPE
INSULATION (optional)
EXTERIOR
PORTION OF
CHIMNEY
INSULATE
TO FORM
SEAL
SHEET
METAL TOP
PLATE
*SIZE TERMINATION
PIPE PER TABLE 27.
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. Refer to figures 38 and 40 for condensate
trap locations.
FIGURE 38
CONDENSATE TRAP AND PLUG LOCATION
(shown with left side exit of condensation)
1-1/2 in.
Trap
(same other right side)
Plug
(same on left side)
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 allen
wrench and remove plug (figure 38) 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 connec
tion use a large flat head screw driver or a 1/2” drive
socket extension and remove plug. Install provided 3/4
NPT street elbow fitting into cold end header box. Use
Teflon tape or appropriate pipe dope.
3 - Install the cap over the clean out opening at the base of
the trap. Secure with clamp. See figure 44 (3/4” drain
connection) or 45 (1/2” drain connection).
4 - Install drain trap using appropriate PVC fittings, glue all
joints. Glue the provided drain trap as shown in figure
44 or 45. Route the condensate line to an open drain.
5 - Figure 41 shows the furnace and evaporator coil using
a separate drain. If necessary, the condensate line
from the furnace and evaporator coil can drain togeth
er. See figures 42 and 43. The field provided vent must
be a minimum 1” to a maximum 2” length above the
condensate drain outlet connection.
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.
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 39.
FIGURE 39
Tubing
Hose Clamp
Barbed Fitting
Field Provided Drain Components
Elbow
6 - If unit will be started immediately upon completion of
installation, prime trap per procedure outlined in Unit
Start-Up section.
Condensate line must slope downward away from the
trap to drain. If drain level is above condensate trap,
condensate pump must be used. Condensate drain
line should be routed within the conditioned space to
avoid freezing of condensate and blockage of drain
line. If this is not possible, a heat cable kit may be used
on the condensate trap and line. Heat cable kit is avail
able from Lennox in various lengths; 6 ft. (1.8m) - kit no.
26K68 and 24 ft. (7.3m) - kit no. 26K69.