Pressure constants for controlling the fans

The ventilation levels and operating modes cannot be adjusted in operation with constant pressure. The functions are disabled.

If `Operation with constant pressure´ parameter set to yes→ initialisation: Ventilation unit runs for 3 minutes with reference volumetric flow and determines the pressure in the air duct. Then the fan selected using the DIP switch runs at the duct pressure established. The other fan conveys the same volumetric flow.

The fans can also be controlled with constant pressure (rather than constant volumetric flow). The pressure is measured in the supply air or exhaust air duct, depending on where the pressure sensor is installed. The relevant fan is controlled as the master fan, the other (slave fan) is operated with the same volumetric flow as the master fan.

To activate operation with constant pressure and to enter the limit values for pressure consistency regulation.

When the pressure loss at the supply air duct changes (e.g. switching over to disk valve), the pressure changes and the master fan again regulates to reference pressure.

Reference volumetric flow

The reference volumetric flow can be set in the Pressure Constancy parameter group.

To set a desired volumetric flow in nominal ventilation, fully open all valves.

The unit is initialised and determines the drop in pressure at the differential pressure sensor with set volumetric flow (reference pressure).

The ventilation unit is controlled such that the reference pressure remains stable within a defined tolerance range.

Reference pressure

The reference pressure can be set in the Pressure Constancy parameter group.

Enter the pressure calculated by the planning office here. This is kept constant during operation.