Lennox SIGNATURE SLP99UHV Installation Instructions Manual page 26

DIRECT VENT APPLICATION
USING EXISTING CHIMNEY
8" - 12"
(203mm - 305mm)
Minimum 12" (305MM)
INSULATION (optional)
above chimney top
plate or average snow
accumulation
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 38
Condensate Piping
This unit is designed for either right- or left-side exit of
condensate piping in upflow applications. In horizontal
applications, the condensate trap must extend below the
unit. An 8" service clearance is required for the conden-
sate trap. Refer to FIGURE 39 and FIGURE 41 for con-
densate trap locations. Figure 39 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 - Use a large flat head screw driver or a 1/2" drive
socket extension and remove plug (figure 31) 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.
NOTE - Cold end header box drain plugs are factory
installed. Check the unused plug for tightness to
prevent leakage.
3 - Install the cap over the clean out opening at the
base of the trap. Secure with clamp. See figure 39.
4 - Install drain trap using appropriate PVC fittings,
glue all joints. Glue the provided drain trap as
shown in FIGURE 47. Route the condensate line
to an open drain. Condensate line must maintain a
1/4" downward slope from the furnace to the drain.
STRAIGHT-CUT OR
ANGLE-CUT IN DIRECTION
OF ROOF SLOPE *
3" - 8"
(76mm-
203mm)
SHOULDER OF FITTINGS
INTAKE PIPE
PROVIDE SUPPORT
OF PIPE ON TOP PLATE
SHEET
ALTERNATE
METAL TOP
INTAKE PIPE
PLATE
3" - 8"
(76mm-
203mm)
EXTERIOR
PORTION OF
CHIMNEY
CONDENSATE TRAP AND PLUG LOCATIONS
(Unit shown in upflow position)
1-1/2 in.
NOTE - In upflow applications where side return
sate trap, filter rack must be installed beyond
condensate trap or trap must be re-located to
avoid interference.
5 - FIGURE 42 and FIGURE 44 shows the furnace and
evaporator coil using a separate drain. If necessary
the condensate line from the furnace and evaporator
coil can drain together. See FIGURE 43, FIGURE
45 and FIGURE 46. Upflow furnace (FIGURE 45)
- In upflow furnace applications the field provided
vent must be a minimum 1" to a maximum 2" length
above the condensate drain outlet connection.
Any length above 2" may result in a flooded heat
exchanger if the combined primary drain line
were to become restricted. Horizontal furnace
(FIGURE 46) - In horizontal furnace applications
the field provided vent must be a minimum 4" to
a maximum 5" length above the condensate drain
outlet connection. Any length above 5" may result in
a flooded heat exchanger if the combined primary
drain line were to become restricted.
NOTE - In horizontal applications it is recommended
to install a secondary drain pan underneath the unit
and trap assembly.
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
40.
Page 26
Plug
(same on left side)
FIGURE 39