Vav Box Control Logic

This airflow setpoint is used by.

Vav box control logic. 6 vav terminal control applications application note pressure independent an improved vav box control strategy employs cascaded proportional integral control loops. Summarizes a detailed analysis of vav box control and selection1 and provides vav boxes sizing criteria that will mini mize lcc in typical applications. Conventional vav box logic. Vav boxes with reheat coils were traditionally controlled using the con trol logic shown in.

A vav box is integral to the ductwork connecting primary ductwork to secondary ductwork. The sup ply airflow setpoint is reset from the zone maximum airflow setpoint when the space is at full cooling proportion ally down the zone minimum when no cooling is required. Vav controls and airflow setpoints figure 1 shows a single duct vav box using pressure independent control logic. A variable air volume vav box is a part of an hvac system in commercial buildings.

Vav box control logic. Dual maximum vav box logic summary title 24 requires dual maximum logic for vav zones with ddc setpoints set minimum and heating maximum setpoints as low as possible minimum allowed by controls is seldom a factor if box properly sized do not use maximum allowed by t 24 just because it is legal cost impact. If the fan airflow is higher than the pre set critical value 70 of the design flow the fan speed is proportionally adjusted based on the airflow ratio. In many cases a variable air volume box is nothing but an assembly of a sheet metal box with a damper and controls inside a control panel.