Instruction Manual

82
Operation
Unit operations should be controlled with
thermostat, or unit controller, never at the
main power supply, except for servicing,
emergency, or complete shutdown of the
unit.
Thermostat Operation
Heating
Thermostat system switch - "Heat"
Thermostat fan switch - "Auto" or "On"
Thermostat temperature set to desired point.
Cooling
Thermostat system switch - "Cool"
Thermostat fan switch - "Auto" or "On"
Thermostat temperature set to desired point.
Air Circulation
Thermostat system switch - "Off"
Thermostat fan switch - "Auto" or "On"
No change of the thermostat temperature.
With these settings, the supply blower will
run continuously but the supply air will not
be heated, cooled, or dehumidified.
System Off
Thermostat system switch - "Off"
Thermostat fan switch - "Auto"
No change of the thermostat temperature.
With these settings the system is shut down,
with the exception of control system power.
Night and Weekend Unoccupied Operation
To reduce the operating time of the unit
when the space is unoccupied, such as nights
and weekends, it is recommended that the
temperature setting be raised about 5°F
while unoccupied during the cooling season
and lowered about 10°F during the heating
season.
Packaged DX Cooling Operation and
Control
When a call for cooling (G and Y1, Y2, etc.)
is made the supply blower motors and
compressors will energize.
Gas Heater Operation
When heat (G and W1, W2, etc.) is called
for the combustion motor starts and the
ignition control is energized. The control
sends 24 VAC to the main gas valve and
high voltage to the igniter. If a burner flame
has been detected within 10 seconds, the
spark is extinguished and the flame
continues. If a flame has not been detected
after 10 seconds, the gas valve closes, the
spark ceases and the induced draft blower
continues to purge the heat exchanger. After
45 seconds of purge, the ignition system will
attempt to light the burners again. Should no
flame be detected after 3 tries, the ignition
control will lock out the system. Power to
the ignition control must be cycled to reset
the heater control.
On a fault the gas train is shut down by a
main limit located in the heat exchanger area
or by an auxiliary limit mounted in the
supply fan compartment.
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME
To prevent motor overheating
compressors must cycle off for a
minimum of 5 minutes.
5 MINUTE MINIMUM ON TIME
To maintain the proper oil level
compressors must cycle on for a
minimum of 5 minutes.
The cycle rate must not exceed 6
starts per hour.
WARNING