AAON M1-011 - Manual (Page 19)

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− Piping from the condensing unit to the indoor air
handler is the responsibility of the installing
contractor.
− Only clean “ACR” tubing should be used.
− Piping should conform to generally accepted
practices and codes.
− Care must be taken not to cross the circuits on
multiple circuit systems.
− Once piped, the interconnecting piping and air
handler MUST BE evacuated to 50 microns or
less; leak checked and charged with refrigerant.
− Make sure air handler thermal expansion valve
bulb is mounted with good thermal contact on the
correct suction line on a horizontal section, close
to the evaporator in the 4 or 8 o’clock position and
well insulated. Care must be taken to ensure the
bulb is mounted on the correct suction line on
multiple circuit systems.
− The suction line (and hot gas bypass line if
present) should be insulated for its entire length
Lines should be fastened and supported according to
local codes.
Air Handler Equipped with Chilled Water Coil
Water supply lines must be insulated with closed cell
type pipe insulation or insulation that includes a vapor
barrier. Lines should be properly fastened, drained
and supported according to local code requirements.
Heating Equipment
When heat is called for, the cooling section is
inoperable except for the indoor blower motor. Actual
heating is accomplished by the air handling unit with
hot water, steam or electric heating capabilities.
Air Handler Equipped with Hot Water Coil
Water supply lines must be insulated, properly
fastened, drained and supported according to local
code requirements.
Air Handler Equipped with Steam Coils
The air handling unit MUST BE installed high enough
to allow for a minimum of one foot (1’) condensate
drop leg off of the steam coil (or as recommended by
the steam trap manufacturer). Lines should be
insulated with approved insulation and be properly
fastened, sloped and supported according to local
code requirements.
Air Handler Equipped with Electric Heating
INSTALLATION IS TO BE ADJUSTED TO OBTAIN
AN AIR TEMPERATURE RISE WITHIN THE RANGE
SPECIFIED ON THE RATING PLATE.
Heating is accomplished by passing electrical current
through a specified amount of resistance heaters
which will produce the required heat. The indoor
blower motor will energize at the same time as the
heaters. Wiring to the air handler must be done in
accordance with local electrical codes and/or
standards. Check specified electrical rating and install
with proper wire size.
Condensate Piping
If the air handler is equipped with cooling, a drain trap
must be connected to the drain pan at the unit. A
condensate connection is provided on each side of the
unit. Condensate piping should be installed according
to local codes. The line should be the same pipe size
as the drain nipple and should pitch downward toward
the building drain.
All cooling coils must have drain pans equipped with
“P” traps to avoid pulling air from outside the unit back
through the drain line. The “P” trap is factory supplied,
and is shipped loose in the control access
compartment for field installation. A plug is provided
for the unused condensate connection. The trap
should be located in warm ambient spaces. An
additional drain pan may be installed under the air
handler, 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.
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.