SYSTEM OPERATION
23
A. Cooling Operation: Low stage cool
1.
Thermostat type is set to two-stage.
2.
Thermostat “Y1” or thermostat “Y1” and “G” input
initiates low stage cooling.
3.
IDT/ODT/Pressure/Loss of Charge Switch circuits are
checked for closed condition. Cooling operation can
proceed only if these circuits are closed.
4.
Low stage compressor output is energized.
5.
Condenser fan motor is energized at low speed.
6.
Air circulating blower is energized at low cool speed
after cool ON delay expires. Cool ON delay timer
begins when thermostat inputs are detected.
7.
Control monitors thermostat, gas valve, flame, and IDT/
ODT/Pressure/Loss of Charge Switches during low
stage cooling.
8.
Thermostat “Y1” or “Y1” and “G” inputs are removed.
9.
Low stage compressor output is de-energized. Low
speed condenser fan motor is de-energized.
10. Air circulating blower remains energized at low cool
speed for the cool OFF delay. Cool OFF delay timer
begins when thermostat input is removed.
11. Control returns to Standby and awaits next thermostat
request.
B. Cooling Operation: High stage cool
Thermostat type is set to two-stage.
Thermostat “Y1” and “Y2” or “Y1”, “Y2” and “G” inputs
initiate high stage cooling.
IDT/ODT/Pressure/Loss of Charge Switch circuits are
checked for closed condition. Cooling operation can proceed
only if these circuits are closed.
1.
Low and high stage compressor outputs are ener-
gized.
2.
Condenser fan motor is energized at high speed.
3.
Air circulating blower is energized at high cool speed
after cool ON delay expires. Cool ON delay timer
begins when thermostat inputs are detected.
Control monitors thermostat, gas valve, flame, and
IDT/ODT/Pressure/Loss of Charge Switches during
high stage cooling operation.
Thermostat “Y1” and “Y2” or “Y1”, “Y2” and “G” inputs
are removed.
Low and high stage compressor outputs are de-
energized.
High speed condenser fan motor is de-energized.
4.
Air circulating blower switches to low cool speed for
the cool OFF delay. Cool OFF delay timer begins
when thermostat input is removed.
Control returns to Standby and awaits next thermostat
request.
A. Continuous Fan Operation
1.
Thermostat “G” input initiates Continuous Fan opera-
tion.
2.
Air circulation blower shall be immediately energized
at the continuous fan speed. For purposes of this
specification, the continuous fan speed shall be the
low heat speed.
3.
Thermostat “G” input is removed.
4.
Air circulation blower is immediately de-energized.
5.
Control returns to Standby and awaits next thermostat
request.
A/GPG15
IGNITION CONTROL SEQUENCE OF OPERATION (CONT.)
