Corrigo ventilation 3.4 manu

36 Chapter 5 Functional description Manual Corrigo Ventilation, revision R

Step controllers and Change-over

The digital output signals "Heating/cooling step 1", "Heating/cooling step 2" and "Heating/cooling

step 3" are used for step controllers during change-over control (see section 5.1.12). They have the

same functions as other step controller outputs, but are set to either heating or cooling depending on

whether heating or cooling is required.

DX cooling with room or extract air control

If DX cooling is used in conjunction with room temperature control or extract air temperature

control, there are two configuration alternatives, DX cooling or DX cooling with exchanger control.

DX cooling without 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.

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.

Y1 = 1