Lennox ML193DFE Series Unit Information page 36

Condensate Piping
This unit is designed for either right- or left-side exit of
condensate piping. Refer to FIGURE 44 and FIGURE 46
for condensate trap locations.
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.
CONDENSATE TRAP AND PLUG LOCATIONS
Trap
(same
on right
side)
1-1/2 in.
FIGURE 44
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 44)
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
50.
4 - Install drain trap using appropriate PVC fittings, glue
all joints. Glue the provided drain trap as shown in
FIGURE 50. Route the condensate line to an open
drain.
5 - FIGURE 48 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 49. The field provided vent
must be a minimum 1" to a maximum 2" length
above the condensate drain outlet connection.
6 - If unit will be started immediately upon completion
of installation, prime trap per procedure outlined in
Unit Start-Up section.
Plug
(same on left side)
Page 36
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 45.
Field Provided Drain Components
Elbow
Tubing
FIGURE 45
Condensate line must slope downward away from the trap
to drain. If drain level is above condensate trap, conden-
sate 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 possi-
ble, a heat cable kit may be used on the condensate trap
and line. Heat cable kit is available from Lennox in various
lengths; 6 ft. (1.8m) - kit no. 26K68 and 24 ft. (7.3m) - kit
no. 26K69.
CONDENSATE TRAP LOCATION
(shown with right side exit of condensation)
Trap can be installed a maximum
of 5ft. from furnace (*PVC only)
Field Provided Vent
1" min. 2" max. above
condensate drain.
1" min.
2" max .
*Piping from furnace must slope down a
minimum 1/4" per ft. toward trap
FIGURE 46
CAUTION
Do not use copper tubing or existing copper condensate
lines for drain line.
Barbed Fitting
Hose Clamp
5' max.
to drain