CORRIGO VENTILATION 3.6 MANU

Manual Corrigo Ventilation, revision V Chapter 5 Functional description 37
DX cooling with exchanger control
When running cascade control, the supply air controller setpoint is normally controlled by the
room/extract air controller output signal.
When DX cooling is activated, the supply air controller setpoint is lowered to five degrees (adjustable)
below the setpoint given by the room/extract air controller. This prevents the DX cooling from being
activated/deactivated too often. If the supply air temperature falls below the setpoint given by the
room/extract air controller, the heat exchanger output will be activated in order to try to maintain the
supply air setpoint given by the room/extract air controller. The output uses P-control with a P-band
of half the setpoint lowering (adjustable, 2.5°C as default). The setpoint given by the room/extract air
controller cannot drop below the set min limit. When there is no longer a cooling demand, the supply
air controller setpoint will return to the value given by the room/extract air controller.
Note: The function cannot be used if the exchanger signal controls a mixing damper.
Example:
The room controller gives a supply air setpoint of 16°C. If there is a cooling demand, the supply air
controller setpoint is lowered to 11°C (16 – 5) and DX cooling is activated. Should the supply air
temperature fall below 16°C, the exchanger output will be activated and reach 100 % output when the
supply air temperature has fallen to 13.5°C (16 - 2.5).
Blocking of DX cooling at low outdoor temperature
DX cooling can be blocked when the outdoor temperature is low. It is possible to block the three
cooling steps individually or to block all DX cooling. The temperature limits are adjustable (+13°C
default) and have a fixed one degree hysteresis.
When two DX cooling steps are used with binary function, the cooling effect is divided into three
steps. The desired blocking level can be set individually for each of these steps.
When three DX cooling steps are used with binary function, the cooling effect is divided into seven
steps. However, the controller still only has three blocking level settings. Therefore, Blocking step 1
will apply to binary steps 1 and 2, Blocking step 2 to binary steps 3 and 4, and Blocking step 3 to
binary steps 5, 6 and 7.
Blocking of DX cooling at low supply air fan speed
When DX cooling is used in conjunction with pressure controlled or flow controlled fans it is possible
to block DX cooling if the supply air fan control signal falls below a preset values. For sequential
control, the blocking level is individually settable for each DX cooling step.
When two DX cooling steps are used with binary function, the cooling effect is divided into three
steps. The desired blocking level can be set individually for each of these steps.
When three DX cooling steps are used with binary function, the cooling effect is divided into seven
steps. However, the controller still only has three blocking level settings. Therefore, Blocking step 1
will apply to binary steps 1 and 2, Blocking step 2 to binary steps 3 and 4, and Blocking step 3 to
binary steps 5, 6 and 7.
Blocking of DX cooling on cooling pump alarm
Corrigo can be configured to block DX cooling on cooling pump alarm.
In- and outputs
Heating Cooling Heating/Cooling
Change-over
DO
DO
DO
Step controller, step 1 (optional)
DO
DO
DO
Step controller, step 2 (optional)
DO
DO
DO
Step controller, step 3 (optional)
DO
Step controller, step 4 (optional)