Daikin APGM3 Service And Troubleshooting page 9

SYSTEM OPERATION
11. Induced draft blower switches from high speed to low
speed and remains energized for post purge period.
12. Air circulating blower remains energized at high heat
speed for High Stage Heat OFF Delay period then
switches to low heat speed for the remainder of the
selected heat OFF delay. Heat OFF delay begins
when "W1" and "W2" inputs are removed.
13. Control returns to Standby and awaits next thermostat
request.
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.
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
energized.
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.
Continuous Fan Operation
1. Thermostat "G" input initiates Continuous Fan
operation.
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.
PCBAG127 CONTROL BOARD
Description
The ignition control is designed for use in gas heating/
electric cooling package equipment (rooftop applications)
and operates with a two stage heat and two stage cooling
system. It is a direct spark ignition system that uses a
22,000 volt spark to ignite the burners. A flame sensor is
used to monitor the flame.
The board has the option of using a single or two stage
thermostat. The board also controls the indoor blower and
has an adjustable heat fan off delay.
There is also a fault recall button for recalling the last 5
fault codes. To recall the fault codes, depress the fault
recall button for at least 2 seconds but not more than 4
seconds. To clear the fault code memory, depress the fault
recall button for at least 5 seconds.
The following tables list the functions for the connectors
and terminals, the timings, and the fault codes for the
PCBAG127 control board.
HIGH VOLTAGE
Disconnect all power before servicing or
installing this unit. Multiple power sources
may be present. Failure to do so may cause
property damage, personal injury or death.
WARNING
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