Service manual

SERVICING
138
SEQUENCE OF OPERATION
AVPTC/MBVC with Single Stage Condensers (24VAC
Legacy Wired Systems)
1.0 Cooling Operation
1.1 On a demand for single stage cooling operation, the
thermostat closes the "G" and "Y" contacts providing
24VAC to the "G", "Y1", and "Y2" terminals at the
integrated air handler control. The integrated AH control
initiates the selected cooling ramping profile after any
blower ON delays have expired. After completing any
blower ON delays and ramping profile, the control
operates the variavble speed ECM motor at the de-
manded airflow.
1.2 The compressor and condensor fan motor is energized
by the closing of the thermostat "Y" contacts.
1.3 The system operates at single stage cooling.
1.4 Upon satisfying the thermostat, the "G" and "Y" thermo-
stat contacts open, removing 24VAC from the both the
outdoor condensor and integrated air handler control.
The compressor and condensor fan motor are both de-
energized immediately. The integrated AH control con-
tinues to operate the ECM blower motor for an OFF delay
period, then applies the off portion of the selected
ramping profile. The ECM blower motor is then de-
energized.
2.0 Heating Operation
2.1 On a demand for auxiliary heat operation, the thermostat
closes the "W1" contacts providing 24VAC to the "W1"
terminal at the integrated air handler control. The
integrated AH control initiates the heating ramping profile
after any blower ON delays have expired. After complet-
ing any blower ON delays and ramping profile, the control
operates the variavble speed ECM motor at the de-
manded airflow.
2.2 The system operates at low stage auxiliary heat.
2.3 If the thermostat demand cannot be met on low stage
auxiliary heat, the thermostat will close the "W2" con-
tacts, providing 24VAC to the "W2" terminal at the
integrated AH control. Thermostat "W1" contacts remain
closed.
2.4 Upon receiving the high stage auxiliary heat demand, the
control operates the ECM blower motor at the demanded
airflow.
2.5 The system operates at high stage auxiliary heat as
demanded by the thermostat.
2.6 Upon satisfying the thermostat, the "W1" thermostat
contacts (or "W1" and "W2" contacts) open, removing
24VAC from the integrated air handler control. The
integrated AH control continues to operate the ECM
blower motor for an OFF delay period, then applies the off
portion of the heating ramping profile. The ECM blower
motor is then de-energized.
3.0 Continuous Fan Operation
3.1 On a demand for continuous fan operation, the thermo-
stat closes the "G" contacts providing 24VAC to the "G"
terminal at the integrated air handler control. The control
energizes the variavble speed ECM motor at 30% of the
air handler's maximum airflow capability.
3.2 Removing the thermostat demand for continuous fan
opens the "G" contacts, removing 24VAC from the
integrated air handler control. The integrated AH control
immediately de-energizes the ECM blower motor.
AVPTC/MBVC with Single Stage Heat Pumps (24VAC
Legacy Wired Systems)
1.0 Cooling Operation
1.1 On a demand for single stage cooling operation, the
thermostat closes the "G", "O", and "Y" contacts provid-
ing 24VAC to the "G", "O", "Y1", and "Y2" terminals atthe
integrated air handler control. The integrated AH control
initiates the selected cooling ramping profile after any
blower ON delays have expired. After completing any
blower ON delays and ramping profile, the control oper-
ates the variavble speed ECM motor at the demanded
airflow.
1.2 The compressor and condensor fan motor is energized
by the closing of the thermostat "Y" contacts. The
reveersing valve is energized by the closing of the
thermostat "O" contacts.
1.3 The system operates at single stage cooling.
1.4 Upon satisfying the thermostat, the "G", "O", and "Y"
thermostat contacts open, removing 24VAC from the
both the outdoor condensor and integrated air handler
control. The compressor, condensor fan motor, and
reversing valve are de-energized immediately. The
integrated AH control continues to operate the ECM
blower motor for an OFF delay period, then applies the
off portion of the selected ramping profile. The ECM
blower motor is then de-energized.
2.0 Heating Operation
2.1 On a demand for heat pump heating, the room thermostat
closes the "G" and "Y" contacts, providing 24VAC to the
"G" and "Y" terminals at the integrated air handler control.
The integrated AH control initiates the heat pump heating
ramping profile after any blower ON delays have expired.
After completing any blower ON delays and ramping
profile, the control operates the variavble speed ECM
motor at the demanded airflow.
2.2 The compressor and condensor fan motor are energized
by the closing of the thermostat "Y" contacts.
2.3 The system operates at single stage heat pump heat.
2.4 If the thermostat demand cannot be met with heat pump
heating, the thermostat will close the "W1/W2" contacts,
providing 24VAC to the "W1" or "W1" and "W2" terminals
at the integrated AH control. Thermostat "G" and "Y"
contacts remain closed.
DELETED 5.6 - 12/16/14