Sequence Of Operation; Cooling Operation - Low And High Stage Cool; Heating Operation - Auxiliary/Emergency Heat; Continuous Fan Operation - Daikin ComfortNet DX16TC Series Service Instructions Manual

SERVICING

SEQUENCE OF OPERATION

DVPTC/MBVC with DX**TC Condenser and CTK0*
Communicating Themostat
The DVPTC or MBVC air handle/modular blower matched
with an DX**TC condensing unit and CTK0* communicating
thermostat constitute a network. The three components, or
subsystems, making up the system communicate with one an-
other 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 destination 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 condenser
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 mo-
tor 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 op-
eration. 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 sequencer
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 han-
dler control along with a fan demand. The control energiz-
es 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 han-
dler control to end continuous fan operation. The integrat-
ed AH control immediately de-energizes the ECM blower
motor.
DVPTC/MBVC with DZ**TC Heat Pump and CTK0*
Communicating Themostat
The DVPTC or MBVC air handle/modular blower matched with
a DZ**TC condensing unit and CTK0* communicating thermo-
stat constitute a network. The three components, or subsys-
tems, 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 destination component.
NOTE: Communicating heat pump systems are designed to
utilize a balance point temperature. The balance point tem-
perature in part controls heat pump operation. If the outdoor
temperature is below the balance point, the heat pump is
disable and only electric heat is available for heating. The
balance point temperature is set via the CTK0* thermostat in
the advanced installer's configuration menu.
The CTK0* thermostat also allows the user to disable the elec-
tric heaters in the air handler/modular blower 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 aquired from the outdoor air
temperature (OAT) sensor included with the ASZC/DSZC heat
pump models. Faults with the sensor will affect heating oper-
ation.
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.
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