3. Place air handler in vertical position.
Filter Size Chart
18 / 24
30 / 36
42 / 48 / 60
Install Condensate Drain
The air handler is provided with ³⁄₄" NPT condensate drain
A field-fabricated secondary drain pan, with a drainpipe 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
When installed in the horizontal position, the air handler must
have a ³⁄₄" drop toward the drain outlet of the drain pan to ensure
proper condensate drainage.
1. Remove the appropriate drain knockouts. See "Drain Pan
Connections" section. You may need to remove the indoor
coil assembly from the cabinet.
2. Remove any web from inside any threaded drain pan hole to
which a drain line is to be connected. Gently remove the web
so as not to damage the coil.
3. 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. Secondary connection is
raised above the bottom of the inside of the pan.
NOTE: When making drain fitting connections to the drain
pan, hand tighten. Using a sealant is recommended.
Overtightening the fittings can split connections on the drain
4. Secondary drain connections, if used, should be connected
to a separate drainage system. Run the secondary drain line
to a place where the occupant would notice if water started
coming from the secondary drain.
5. Install a 3" trap in both the primary and secondary drain lines
as close to the unit as practical. Make sure the top of the trap
is below the connection to the drain pan to allow complete
drainage of the pan.
NOTE: Horizontal runs must also have an anti-siphon air vent
(standpipe) installed ahead of the horizontal run. See "Typical
Condensate Drain Connection" in this section. An extremely
long horizontal run may require an oversized drain line to
eliminate air trapping.
16" x 20"
18" x 20"
18" x 25"
Typical Condensate Drain Connection
(secondary drain not shown)
A. Air handler
D. Anti-siphon air vent
B. Drain connection
E. Drain trap
C. Drain line
F. Auxiliary drain pan
NOTE: Do not operate air handler without a drain trap. 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.
6. 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.
7. Insulate the drain lines where sweating could cause water
Test condensate 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 completely, 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.
Install ductwork in accordance with NFPA 90B and any local
Connect supply air duct to the flange on top of the air
handler. If an isolation connector is used, it must be
A return air duct system is recommended. If the unit is
installed in a confined space or closet, a return connection
must be run, full size, to a location outside the closet.