AAON F1-024, Installation, Operation & Maintenance Manual

Page: 21 / 56

21
All cooling coils must have drain pans
equipped with “P” traps to avoid pulling air
from outside the unit back through the drain
line. All drain connection ports are sealed.
Knock out only the connection port to be
used. The trap should be located in warm
ambient spaces. An additional drain pan
may be installed under the air handling unit,
and should include a separate drain line for
overflow from the primary drain. An air
break should be used with long runs of
condensate lines.
Unit may be equipped with more than one
condensate drain pan connection. A p-trap
and drain line must be installed on at least
one section’s drain connection, with the p-
trap not to exceed 6” from the drain
connection. The lines should be the same
pipe size or larger than the drain connection,
include a p-trap, and pitch downward toward
drain. An air break should be used with long
runs of condensate lines.
Draw-through cooling coils will have a
negative static pressure in the drain pan area.
This will cause an un-trapped drain to back
up due to air being pulled up through the
condensate drain piping.
Condensate drain trapping and piping should
conform to all applicable governing codes.
Note: The drain pan connection(s) is a 3/4”
MPT fitting.
Drain pans in any air conditioning
equipment, even when they have a built-in
slope to the drain, will have moisture present
and will require periodic cleaning to prevent
any build-up of algae or bacteria. Cleaning
of the drain pans will also prevent any
possible plugging of the drain lines, and
overflow of the pan itself. Some means to
clean out the “P” trap should be provided.
Only qualified personnel should clean drain
pans, drain lines, or the insides of
equipment.
Electrical
Check the unit data plate to make sure it
agrees with the power supply. Connect
power to the unit according to the wiring
diagram provided with the unit.
The power and control wiring may be
brought in through the holes provided on the
unit. Protect the branch circuit in accordance
with code requirements. If the control wires,
are to run inside the same conduit, use 600-
volt wire or as required by applicable codes.
The units must be electrically grounded in
accordance with the National Electric Code,
ANSI / UL 1995 when installed if an
external source is utilized; in Canada use
current C.S.A. Standard C22.2, No. 236,
Canadian Electric Code Part 1.
Power wiring is to the unit terminal control
board. The manufacturer has done all wiring
beyond this point. Power can be applied to
the unit after the control wiring is connected,
and startup checks are complete.
Unit should not be operated without
p-traps. Failure to install a p-traps
may result in overflow of condensate
water.
CAUTION