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SERVICING
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 heat pump. 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 heat pump energizes the compressor and condens-
er fan motor at the appropriate low stage speeds. The
reversing valve is also energized.
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 heat pump. The heat pump in turn
sends a request for high stage fan speed to the air handler/
modular blower. The AH control increases the blower
speed to the high stage cooling speed.
1.6
The heat pump’s unitary control energizes the high stage
compressor solenoid and switches the condenser fan mo-
tor to high speed. The reversing valve remains energized.
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 heat pump de-energizes the compressor,
condenser fan motor, and reversing valve. The UC control
continues providing a fan request until any cooling blower
OFF delays have expired.
2.0 Heating Operation
Outdoor Temperature Above the Heat Pump Balance Point
2.1
The CTK0* thermostat sends a request for the outdoor air
temperature to the heat pump. The heat pump returns an
outdoor air temperature that is above the balance point
temperature. Heat pump heating is enabled.
2.2
The CTK0* thermostat sends a request for low stage
heat pump heating to the unitary (UC) control in the heat
pump. The UC control receives the command and process-
es any compressor and fan delays.
2.3
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.
2.4
The condenser energizes the compressor and condenser
fan motor at the appropriate low stage speeds.
2.5
The system operates at low stage heat pump heating.
2.6
If the thermostat demand cannot be met on low stage
heat pump heating, the CTK0* thermostat sends a request
for high stage heat pump heating to the heat pump. The
heat pump in turn sends a request for high stage fan
speed to the air handler/modular blower. The AH control
increases the blower speed to the high stage heat pump
heating speed.
2.7
The heat pump’s unitary control energizes the high stage
compressor solenoid and switches the condenser fan mo-
tor to high speed.
2.8
The system operates at high stage heat pump heating.
2.9
If the thermostat demand cannot be met on high stage
heat pump heating, the CTK0* thermostat sends a request
for auxiliary heat to the air handler/modular blower.
2.10
Upon receiving a demand for auxiliary heat, the air
handler control determines the appropriate airflow for
high stage heat pump + auxiliary heat operation and oper-
ates the ECM blower motor at that airflow demand. The
air handler control determines which airflow demand is
greatest and applies that demand when operating the ECM
blower motor.
2.11
The system operates at high stage heat pump heating
plus auxiliary heat.
2.12
Once the thermostat demand is satisfied, the CTK0*
thermostat commands the heat pump to end heat pump
heating operation. The compressor and outdoor fan motor
are de-energized.
The air handler/modular blower is commanded to end
auxiliary heat operation. The air handler control de-ener-
gizes the electric heat sequencer outputs. The ECM blow-
er motor remains energized until any blower OFF delay
timing has expired.
Outdoor Temperature Below the Heat Pump Balance Point
2.1
The CTK0*** thermostat sends a request for the outdoor
air temperature to the heat pump. The heat pump returns
an outdoor air temperature that is below the balance point
temperature. Heat pump heating is disabled.
2.2
The CTK0*** thermostat sends a request for auxiliary
heat to the air handler/modular blower.
2.2
The air handler control energizes the ECM blower motor
at the auxiliary heat speed. The electric heat sequencer
outputs are also energized, thus energizing the electric
heaters.
2.3
The system operates at auxiliary heat.
2.4
Once the thermostat demand is satisfied, the CTK0*
thermostat commands the air handler/modular blower
to end auxiliary 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 contro-
ladjustable via the CTK0* thermostat. The compressor
delay is intended to eliminate compressor noise during the
reversing valve shift.) The compressor will energized (or
re-energized) at high stage.
3.2
If the thermostat demand for continuous fan is removed,
the CTK0* thermostat commands the integrated air han-
dler control to end continuous fan operation. The integrat-
ed AH control immediately de-energizes the ECM blower
motor.