Lennox CB26UH Unit Information page 12

Install Condensate Drain
The air handler is provided with ¾" NPT condensate drain
connections.
IMPORTANT
A field−fabricated secondary drain pan, with a drain
pipe to the outside of the building, is required in all
installations over a finished living space or in any
area that may be damaged by overflow from the main
drain pan. In some localities, local codes may require
an secondary drain pan for any horizontal installa-
tion.
Make sure the unit is sloped (up to 1/4 inch) so that the drain
pan will empty completely without water standing in the
pan. See figure 12.
THIS CORNER
SHOULD BE
5/8I (+/- 1/8I)
HIGHER THAN
DRAIN CORNER
DRAIN CORNER
FIGURE 12
1. Remove the appropriate drain knockouts. If necessary,
remove the indoor coil assembly from the cabinet.
2. Connect primary drain line connection to the primary
drain pan connection. The primary drain connection is
flush with the bottom of the inside of the pan. Secon-
dary connection is raised above the bottom of the in-
side of the pan.
NOTE − When making drain fitting connections to the
drain pan, hand tighten the fitting and use a sealant.
Overtightening the fittings can split connections on the
drain pan.
3. Secondary drain connections, if used, should be con-
nected to a separate drainage system. Run the secon-
dary drain line to a place where the occupant would be
sure to notice any drainage from the drain.
4. Install a 3" trap in both the primary and secondary drain
lines as close to the unit as practical (see figure 13).
Make sure the top of the trap is below the connection
to the drain pan to allow complete drainage of the pan.
Typical Condensate Drain Connection
NOTE − Horizontal runs over 15 ft. long must also have
an antisiphon air vent (standpipe) installed ahead of
the horizontal run (See figure 13). An extremely long
horizontal run may require an oversized drain line to
THIS CORNER
eliminate air trapping.
SHOULD BE
5/8I (+/- 1/8I)
HIGHER THAN
NOTE − Do not operate air handler without a drain trap.
DRAIN CORNER
The condensate drain is on the negative pressure side
of the blower; therefore, air being pulled through the
condensate line will prevent positive drainage without
a proper trap.
5. Route the drain line to the outside or to an appropriate
drain. Drain lines must be installed so they do not block
service access to the front of the air handler. A 24"
clearance is required for filter, coil, or blower removal
and service access.
NOTE − Check local codes before connecting the drain
line to an existing drainage system.
6. Insulate the drain lines where sweating could cause
water damage.
Test Condensate Drain
Test the drain pan and drain line after installation:
1. Pour several quarts of water into drain pan, enough to
fill drain trap and line.
2. Check to make sure the drain pan is draining complete-
ly, no leaks are found in drain line fittings, and water is
draining from the end of the primary drain line.
3. Correct any leaks found.
Page 12
(Secondary Drain Not Shown)
DRAIN CONNECTION
AIR
HANDLER DRAIN LINE
DRAIN PAN
12" Max.
DRAIN TRAP
FIGURE 13
ANTI−SIPHON
AIR VENT
1" Min.
3" Min.