Trane TRG-TRC014-EN manual Controlling System Static Pressure, Fan Outlet Static-PressureControl

period four

Fan Modulation

notes

Controlling System Static Pressure

▲Fan outlet static-pressure control

▲Supply duct static-pressure control

▲Optimized static-pressure control

Figure 90

System Static-Pressure Control

Each of these fan-capacity control methods requires a signal from a controller that monitors static pressure, using a sensor located somewhere in the supply- duct system. This controller compares the sensed pressure to a set point and modulates the fan capacity to maintain a set point at that sensor location.

There are three common methods for sensing and controlling system static pressure. They are: fan outlet static-pressure control, supply duct static- pressure control, and optimized static-pressure control.

Fan Outlet Static-Pressure Control

sensor located at fan outlet

static pressure sensor

VAV terminal units

supply fan

Figure 91

For the fan outlet static-pressure control method, the static pressure sensor is mounted near the outlet of the main supply fan. The controller is set to maintain the static pressure required at design flow.

The appeal of this method is that the sensor can be factory-installed and tested, resulting in greater reliability and no field installation cost. If fire dampers are

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