GSX14 Service Manual

SERVICING
141
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.
4.0 Defrost Operation
4.1 The control in the outdoor unit determines when a defrost
cycle is needed. Upon determing that a defrost cycle is
needed, the outdoor control de-energizes the condensor
fan motor and energizes the reversing valve. A "W1"
signal is sent from the outdoor unit control to the
integrated air handler control.
4.2 The air handler control energizes the eletric heat
sequencer output to turn on the electric heaters. The
appropriate airflow demand is provided to the motor
(greater of heat pump or auxiliary heat).
4.3 At the conclusion of the defrost cycle, the outdoor unit
control removes the "W1" output to the integrated air
handler control, de-energizes the reversing valve and re-
energizes the condensor fan motor.
5.0 Emergency Heat Operation
5.1 On a demand for emergency heat operation, the thermo-
stat closes the "W1/W2" 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 emer-
gency heat airflow.
5.2 The system operates at emergency heat.
5.3 Upon satisfying the thermostat emergnecy heat demand,
the "W1" thermostat 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
AVPTC/MBVC with ASXC/DSXC Condenser and CTK0*
Communicating Themostat
The AVPTC or MBVC air handle/modular blower matched
with an ASXC or DSXC condensing unit and CTK0* commu-
nicating thermostat constitute a network. The three compo-
nents, or subsystems, making up the system communicate
with one another with information passed between all three
components. This leads to a somewhat non-traditional
manner in which the system components receive commands
for system operation. All system commands are routed from
the component through the network to the appropriate des-
tination component.
NOTE: The individual subsystems will cease operation if the
request for operation is NOT refreshed after 5 minutes. This
is a built-in safe guard to prevent the possibility of runaway
operation.
1.0 Cooling Operation - Low and High Stage Cool
1.1 The CTK0* thermostat sends a request for low stage
cooling through the network to the unitary (UC) control
in
the condenser. The UC control receives the command
and processes any compressor and fan delays.
1.2 The UC control sends a request for low stage fan speed
to the air handler/modular blower. The blower energizes
the ECM blower motor at the appropriate speed.
1.3 The condenser energizes the compressor and con-
denser fan motor at the appropriate low stage speeds.
1.4 The system operates at low stage cooling.
1.5 If the thermostat demand cannot be met on low stage
cooling, the CTK0* thermostat sends a request for high
stage cooling to the condenser. The condenser in turn
sends a request for high stage fan speed to the air
handler/modular blower. The blower increases the
blower speed to the high stage cooling speed.
1.6 The condenser's unitary control energizes the high stage
compressor solenoid and switches the condenser fan
motor to high speed.
1.7 The system operates at high stage cooling.
1.8 Once the thermostat demand is satisfied, the CTK0*
thermostat commands the UC control to end cooling
operation. The condenser de-energizes the
compressorand condenser fan motor. The UC control
continues providing a fan request until any cooling blower
OFF delays have expired.
2.0 Heating Operation - Auxiliary/Emergency Heat
2.1 The CTK0* thermostat sends a request for emergency
heat to the air handler/modular blower.
2.2 The air handler control energizes the ECM blower motor
at the emergency heat speed. The electric heat se-
quencer outputs are also energized, thus energizing the
electric heaters.
2.3 The system operates at emergency heat.
2.4 Once the thermostat demand is satisfied, the CTK0*
thermostat commands the air handler/modular blower to
end emergency heat operation. The air handler control
de-energizes the electric heat sequencer outputs. The
ECM blower motor remains energized until any blower
OFF delay timing has expired.
3.0 Continuous Fan Operation
3.1 With a demand for continuous fan operation, the CTK0*
thermostat sends a fan request to the integrated air
handler control along with a fan demand. The control
energizes the variavble speed ECM motor at fan demand
provided by the thermostat. The fan demand provided by
the thermostat will be 30%, 50%,or 70% of the air
handler's maximum airflow capability. The continuous
fan demand is set from the thermostat as low, medium,
or high.
3.2 If the thermostat demand for continuous fan is removed,
the CTK0* thermostat commands the integrated air
handler control to end continuous fan operation. The
integrated AH control immediately de-energizes the
ECM blower motor.