AAON HA-50 - Manual (Page 4)

4
The HA Series units are designed for fast, easy installa-
tion as a self-contained cooling unit for outdoor instal-
lation only.
UNPACKING
When received, the unit should be inspected and
checked for damage that might have occurred in transit.
If damage is found, it should be noted on the carrier's
Freight Bill. A request for inspection by the carrier's
agent should be made in writing at once.
Before lifting the unit, be sure that all shipping material
has been removed from the unit.
Once shipping material has been removed, check inside
the unit control compartment for the field installed "P-
Trap" condensate connector. Also check the inlet air
opening for the filter rails and filters that are shipped
loose with the unit for field installation.
SETTING THE UNIT
If cable or chains are used to hoist the unit, care should
be taken to prevent damage to the cabinet.
Secure hooks and cables at all lifting points / lugs
provided on the unit. Hoist the unit to a point directly
above the pad, and lower unit into place. Make sure unit
is properly seated on the pad.
ELECTRICAL
A complete set of unit specific wiring diagrams in both
ladder and point-to-point form are provided with the
unit.
Check the unit data plate to make sure it agrees with the
power supply. The power and control wiring may be
brought to the unit through a hole in the side of the unit.
Protect the branch circuit in accordance with code re-
quirements and connect power to the unit according to
the wiring diagram provided with the unit. If the control
wires are to run inside the same conduit, use 600 volt
wire or as required by applicable code. The unit must be
electrically grounded in accordance with the National
Electric Code.
Power wiring is to the unit terminal block or compressor
contactor. All wiring beyond this point is done by the
manufacturer.
After connecting the control wiring to the unit, power
may now be applied to the unit. Be sure that the
evaporator blower and condenser fan(s) rotate in the
proper direction (this applies only to units having three
phase blower motor).
OWNER'S INFORMATION
▲
On three phase units the rototation must be
checked on ALL MOTORS AND COMPRESSORS.
SCROLL COMPRESSORS ARE DIRECTIONAL.
Rotation must be checked on start-up by a
qualified service technician using
suction and discharge gauges.
Scroll compressors will FAIL if run in the wrong
direction. Blower and condenser rotation
should be checked and only be altered if
necessary at the power connection.
! CAUTION
COOLING SECTION • DIRECT EXPANSION (DX)
All direct expansion refrigeration systems are factory
assembled, charged with refrigerant, tested and oper-
ated. On 13 - 25 ton units the refrigerant system includes
dual circuit evaporator and condenser coils providing
two stages of cooling. On 30 - 40 ton units the refrigera-
tion system includes a four circuit evaporator coil and
two dual circuited condensor coils providing two or four
stages (optional) of cooling. These systems are provided
with liquid line filter driers, expansion valves and fully
hermetic compressors. Compressors are equipped with a
positive pressure forced lubrication system and crank-
case heater. The air cooled condenser coil(s) is con-
structed of copper tubes with aluminum fins, the air is
pulled through with propeller fans. The evaporator coil
is draw through, made of copper tubes with aluminum
fins.
NOTE: Crankcase Heater Operation
Some units are equipped with a compressor crackcase
heater, which should be energized at least 24 hours prior
to setting the thermostat for cooling operation.
Never cut off the main power supply to the unit, except
for complete shutdown. When power is cut off from the
unit, any compressors using crankcase heaters cannot
prevent refrigerant migration. This means the compres-
sor will cool down, and liquid refrigerant will accumu-
late in the compressor. Since the compressor is designed
to pump refrigerant gas, damage may occur when power
is restored.
If power must be cut off for more than an hour, turn the
thermostat system switch to "OFF", and leave it off until
the main power switch has been turned on again for at
least twenty four hours for units with compressor crank-
case heaters. This will give the crankcase heater time to
clear any liquid accumulation out of the compressor
before it is required to run.
Always control the system from the thermostat, or con-
trol panel, never at the main power supply (except for
emergency or for complete shutdown of the system).
The refrigeration section of these appliances has been
found acceptable with applicable provisions of "ANSI /
UL 1995" and current "C.S.A. Standard C22.2" by E.T.L.
▲
! WARNING
Electric shock hazard. Can cause injury or death.
Before attempting to perform any service or
maintenance, turn the electrical power to unit to
OFF at disconnect switch(es). Unit may have
multiple power supplies.
Failure to observe the following instructions will
result in premature failure of your system, and
possible voiding of the warranty.