BENDIX BW2789 manual Installation, Series Configuration

INSTALLATION

The DRO valve can be installed in two configurations, series or parallel.

Series Configuration

The series configuration, shown in Figure 3, allows all the compressor discharge air to pass through the valve and into the dryer or reservoir.

		TO THE
		CONTROL
	GOVERNOR	PORT OF THE
		AIR DRYER
		FROM THE
		RESERVOIR
	DRO	TO THE SUPPLY
	UNLOADER	PORT OF THE
COMPRESSOR	VALVE	AIR DRYER

FIGURE 3 - SERIES CONFIGURATION

Parallel Configuration

The parallel configuration, shown in Figure 4, allows the DRO unloader valve to be mounted using a branch circuit. This branch circuit provides the flexibility of installing the unloader valve in a more convenient location. The branch line should not run uphill or have kinks or sharp bends that may trap condensed liquids.

TO THE SUPPLY

PORT OF THE AIR

DRYER

TO THE

GOVERNORCONTROL

PORT OF THE

3.For series installation, install a discharge line from the compressor to the DRO valve, as shown in Figure 3. For parallel installation add another discharge line into the existing compressor discharge line using a tee fitting. Connect the opposite end of this new line to the DRO unloader valve as shown in Figure 4. The valve must be at the same height or lower than the discharge line.

4.For a series configuration, the delivery line out of the DRO should be connected to the air brake dryer or reservoir tank.

5.For a parallel configuration, the delivery port out of the DRO must be plugged.

6.The supply and delivery ports are 22 mm metric threads. The control port is 12 mm metric threads. Consult a fitting supplier for conversion fittings.

7.Make sure there is a line from the governor unloader port to the DRO valve control port.

8.Test all connections for leaks.

9.Start the engine and allow the system to reach cut- out pressure. The valve should open allowing air to exit the exhaust port. A silencer, shown in Figure 2, is recommended to reduce the noise level out of the DRO valve when exhausting. Bendix provides a silencer that snaps onto the exhaust port the DRO.

10.Fan the brakes until system cut-in is reached. The DRO valve exhaust should shut allowing the air brake system pressure to increase until cut-out pressure is reached.

Note: The operating range of the DRO unloader valve is from -40°F to 300°F. The DRO valve must be installed with sufficient discharge line length to prevent the air dryer inlet

DRO

AIR DRYER

FROM THE PORT 21 MUST RESERVOIR BE PLUGGED

temperature from exceeding 160°F.

To prevent failure or freeze-ups, the control air into the DRO valve must be free of liquid water and fluids and the maximum inlet pressure to the DRO valve is 174 PSI.

UNLOADER

VALVE

FIGURE 4 - PARALLEL CONFIGURATION

1.Locate a position in the discharge line of the compressor where the DRO valve can be mounted. The valve must be mounted at the same height or below the compressor outlet.

2.Secure the DRO valve using 5/16” grade 5 or higher bolts. It is not recommended to install the valve directly on to the engine or compressor.

2