SYSTEM OPERATION
24
The CoolCloud HVAC app also allows the user to disable
the electric heaters in the air handler depending on the
outdoor temperature. The electric heaters are disabled If
the outdoor temperature is above the set point. All heating
is supplied by the heat pump.
The outdoor air temperature is acquired from the outdoor
air temperature (OAT) sensor included with the ASZC/
DSZC heat pump models. Faults with the sensor will affect
heating operation.
1.0 Heating Operation
Outdoor Temperature Above the Heat Pump Bal
-
ance Point
1.1
The ComfortBridge control algorithm 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
as mentioned above, even if the temperature is above
the balance point, the internal algorithms might still have
determined the heat pump isn’t capable of getting the job
done. If this is the case, the heat pump will not be active
until the algorithm resets.
1.2
The ComfortBridge control algorithm 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 processes any compressor and fan delays.
NOTE: The main control algorithm might start with a
high stage heating call and skip the low stage step if
necessary.
1.3
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.
1.4
The condenser energizes the compressor and
condenser fan motor at the appropriate low stage speeds.
1.5
The system operates at low stage heat pump heating.
1.6
If the thermostat demand cannot be met on low stage
heat pump heating. The heat pump in turn sends a request
for high stage fan speed to the air handler. The AH control
increases the blower speed to the high stage heat pump
heating speed.
1.7
The heat pump’s unitary control energizes the high
stage compressor solenoid and switches the condenser
fan motor to high speed.
1.8
The system operates at high stage heat pump heating.
1.9
If the thermostat demand cannot be met on high stage
heat pump heating.
1.10
Upon receiving a demand for auxiliary heat, the air
handler control determines the appropriate airflow for high
stage heat pump + auxiliary heat operation and operates
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.
1.11
The system operates at high stage heat pump
heating plus auxiliary heat.
1.12
Once the thermostat demand is satisfied, the
ComfortBridge control algorithm commands the heat pump
to end heat pump heating operation. The compressor and
outdoor fan motor are de-energized.
The air handler is commanded 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.
2.0 Outdoor Temperature Below the Heat Pump
Balance Point
2.1
The indoor board 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 outdoor board sends a request for auxiliary heat to
the air handler.
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
ComfortBridge control algorithm commands the air handler
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 Defrost Operation
3.1
While the system is operating in heat pump heating
(see
2.0 Heating Operation
), the control in the outdoor
unit may determines that a defrost cycle is needed. Upon
determining that a defrost cycle is needed, the UC control
de-energizes the condenser fan motor and energizes the
reversing valve.
Summary of Contents for ASXC16
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