AAON RK-60 - Manual (Page 5)

5
GAS HEATING SYSTEM
The heating section is for use with natural gas supply
pressure of 6" to 10.5" Water Column. The unit can also
be fired on propane gas with a supply pressure to the
valve of 11" to 12" Water Column. A 1/8" pressure tap
must be supplied by the installer in the piping just ahead
of the gas valve. The rating plate on the furnace shall be
inspected to make sure that the unit is stamped for the
proper gas. The pressure tap on the outlet end of the gas
valve should be removed and the valve adjusted for the
proper manifold pressure to 3.5" on natural gas and
10.5" for propane gas.
The burner area is not sealed and combustion air is
supplied by a centrifugal blower which draws in fresh air
through a protected opening. This air is introduced into
the burner tubes by the action of the induced draft
blower. This insures an even flow of primary and second-
ary air to the burners.
The heating system and safety controls are 100% tested
on each unit before it leaves the factory.
INSTALLATION IS TO BE ADJUSTED
TO OBTAIN AN AIR TEMPERATURE RISE
WITHIN THE RANGE SPECIFIED ON THE
RATING PLATE.
The units are equipped with a direct spark ignition
system which proves the burner operation during each
call for heat.
Power to the ignition control is 24 volts to reduce haz-
ards. Burner ignition is by a high intensity spark.
When heat is called for, the cooling system is inoperable
except for the indoor blower motor. Actual heating is
accomplished by firing gas into the heat exchanger
assembly.
ELECTRIC HEATING SYSTEM
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.
STEAM OR HOT WATER HEATING SYSTEM
Heating is accomplished by passing steam or hot water
through the steam or hot water coil assembly.
COOLING SECTION • DX
All direct expansion refrigeration systems are factory
assembled, charged with refrigerant, tested and oper-
ated. On all units 8 ton and larger the refrigerant system
includes multiple circuit evaporator and condenser coils
providing two or more stages 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. The air cooled condenser coil(s) is constructed 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.
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.
NOTE: Crankcase Heater Operation
Some units are equipped with a compressor crankcase
heater, which should be energized at least 24 hours prior
to setting the thermostat for cooling operation.
COOLING SECTION • CHILLED WATER
or NON-COMPRESSORIZED UNIT
Chilled water or non-compressorized units have factory
installed coils. These systems are provided with internal
header connections for field connection. Coils are alumi-
num fin / copper tube construction.
HEATING & COOLING SYSTEMS
NORMAL OPERATION
HEATING
Set the thermostat system switch to "HEAT".
Set the thermostat fan switch to "AUTO" or "ON".
Set the thermostat temperature at the desired point.
COOLING
Set the thermostat system switch to "COOL".
Set the thermostat fan switch to "AUTO" or "ON".
Set the thermostat temperature at the desired point.
AIR CIRCULATION
Set the thermostat system switch to "OFF".
Set the thermostat fan switch to "ON".
Do not change temperature setting.
With these settings, the air circulating blower will run
continuously but the air will not be heated or cooled.
SYSTEM OFF
Set the thermostat system switch to "OFF".
Set the thermostat fan switch to "AUTO".
Do not change temperature setting.
With these settings, the system is shut down, with the
exception of the control system power (24 volts), and the
crankcase heater of the compressor (about 60 watts).
DO NOT TURN OFF THE MAIN POWER SWITCH.
NIGHT AND VACANT WEEKEND OPERATION
If it is desired to reduce the operating time during the
night, and during periods when the space is unused,
it is recommended that the temperature setting be
raised about five degrees during these periods of the
cooling season, and lowered about ten degrees during
the heating season.