AAON RM-030 - Manual (Page 3)

3
OWNER'S INFORMATION
The units are designed as self-contained heating, cooling
or combination units for outdoor installation only, using
the refrigerant shown on the rating plate, chilled water,
natural or propane gas, electric resistance, steam or hot
water heating.
WARNING
Failure to observe the following instructions will result
in premature failure of your system, and possible void-
ing of the warranty.
DIRECT EXPANSION (DX) COOLING UNITS
Never cut off the main power supply to the unit, except
for complete shutdown. When power is cut off from the
unit, compressors with crankcase heaters cannot pre-
vent refrigerant migration. The compressor will cool
down, and liquid refrigerant will accumulate in the
compressor. The compressor is designed to pump only
refrigerant gas and 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 on units with compressor crank-
case heaters. This will give the crankcase heater time to
clear 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 in an
emergency or complete shutdown of the system).
During the cooling season, if the air flow is reduced due
to dirty air filters or other reasons, the cooling coils will
get too cold and result in excessive liquid return to the
compressor. As the liquid concentration accumulates,
oil is washed out of the compressor, leaving it starved for
lubrication.
The compressors must be on a minimum of 4 minutes
and off for a minimum of 5 minutes. The cycle rate must
not exceed 8 starts per hour.
THE COMPRESSOR LIFE WILL BE SERIOUSLY
SHORTENED BY RESULTING REDUCED LUBRICA-
TION, AND THE PUMPING OF EXCESS AMOUNTS
OF LIQUID OIL AND REFRIGERANT.
GAS OR ELECTRIC HEATING
The system is designed to heat a given amount of air each
minute it operates. If the amount of air heated is greatly
reduced (approximately 1/3 capacity), the heat ex-
changer / heater coil temperature will increase above
acceptable level and result in shut down by a high
temperature safety switch incorporated either in the
heat exchanger or the heater area.
GAS HEAT UNITS - WARNING: If, due to safety switch
shut off or gas supply shut off failure; ALWAYS CLOSE
MANUAL GAS VALVE TO UNIT PRIOR TO ANY
ELECTRICAL SERVICE.
PROLONGED OVERHEATING OF THE HEAT
EXCHANGER WILL SHORTEN ITS LIFE.
CAUTION: While the following incorrect operations
may not cause damage to the system, they will impair
the performance, and may cause the built-in safety
devices to cut the system off completely.
1. LOW AMBIENT OPERATION
The cooling section of a direct expansion (DX) unit
will not operate properly when the outdoor tempera-
ture is below 55
°
F. Outside air intake options are
necessary if operation below 55
°
F is expected.
2. MULTIPLE UNIT OPERATION
When several units are used in conditioning the
space, and any are combination heating-cooling
units, all system thermostat switches must be set at
either heating, cooling, or set at "off". Do not run
part of a system switched to an opposite mode.
Cooling only units should be switched to "off" at the
thermostat during the heating season.
WIRING DIAGRAMS
A complete set of unit specific wiring diagrams in both
ladder and point-to-point form are laminated in plastic
and located inside the control compartment door.
CONDENSATE PIPING
A drain trap is to be connected to the drainpan. If codes
require a condensate drain line, it should be the same
pipe size as the drain nipple and should pitch downward
toward drain.
The condensate drain pipe ("P" trap) is factory supplied
and shipped in the control access compartment for field
installation. An air break should be used with long runs
of condensate lines.
▲
! 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.
AIRFLOW IS TO BE ADJUSTED AFTER
INSTALLATION TO OBTAIN AN AIR
TEMPERATURE RISE WITHIN THE RANGE
SPECIFIED ON THE RATING PLATE.
DUE TO JOB SPECIFICATION REVISIONS,
IT MAY BE NECESSARY TO ADJUST OR
CHANGE THE SHEAVE OR PULLEY TO
OBTAIN THE DESIRED AIRFLOW
AT THE TIME OF INSTALLATION.
▲
! CAUTION
START-UP TECHNICIAN MUST CHECK BLOWER
MOTOR AMPERAGE TO ENSURE THAT THE
AMPERAGE LISTED ON THE MOTOR NAMEPLATE
IS NOT EXCEEDED.