BENDIX BW2077 manual Operation & Leakage Tests, Rebuilding the AD-ISAIR Dryer

WARNING!

This air dryer is intended to remove moisture and other contaminants normally found in the air brake system. Do not inject alcohol, anti-freeze, or other de-icing substances into or upstream of the air dryer. Alcohol is removed by the dryer, and reduces the effectiveness of the device to dry air. Use of these or other substances can damage the air dryer and will void the warranty.

OPERATION & LEAKAGE TESTS

(For additional information order "Air Leakage Video" BW2327)

1.Check all lines and fittings leading to and from the air dryer for leakage and integrity. Repair any leaks found.

2.Build up system pressure to governor cut-out and note that the AD-IS®air dryer purges with an audible escape of air. Watch the system pressure for leakage for a ten minute period. If pressure drop exceeds, for a single vehicle - 1 psi/minute from either service reservoir; or for tractor trailer - 3 psi/minute from either service reservoir, inspect the vehicle air systems for sources of leakage and repair them.

3.Caution: Be sure to wear safety glasses in case of a purge blast. Check for excessive leakage around the purge valve of the dryer, not in the purge cycle, with the compressor in the loaded mode (compressing air). Apply a soap solution to the purge valve exhaust port and observe that leakage does not exceed a 1” bubble in 1 second. If the leakage exceeds the maximum specified, refer to section entitled Troubleshooting, Symptom 4.

4.Build up system pressure to governor cut-out and note that one of the AD-IS®EverFlow™ assembly dryers purges with an audible burst of air, followed immediately by approximately 30 seconds of air flowing out of the purge valve. “Fan” the service brakes to reduce system air pressure to governor cut-in. Note that the system once again builds to full pressure and is followed by the AD-IS®EverFlow™ assembly other air dryer purge. If system does not follow this pattern, refer to section entitled Troubleshooting, Symptoms 1, 2 and 3. Check the operation of the end cover heater and thermostat assembly during cold weather operation as follows:

A.Electric Power to the Dryer NOTE: The EverFlow™ assembly should be wired through the ignition and not the battery. With the ignition or engine kill switch in the RUN position, check for voltage to the heater and thermostat assembly using a voltmeter or test light. Unplug the electrical connector at the air dryer and place the test leads on each of the connections of the female connector on the vehicle power lead. If there is no voltage, look for a blown fuse, broken wires, or corrosion in the vehicle wiring harness. Check to see if a good ground path exists. The EverFlow™ assembly

requires the correct electrical voltage to operate properly.

B.Thermostat and Heater Operation (Refer to Figure 3). NOTE: These tests can only be conducted during cold weather operation. Turn off the ignition switch and cool the thermostat and heater assembly to below 40 degrees Fahrenheit. Using an ohmmeter, check the resistance between the electrical pins in the air dryer connector half. The resistance should be 1.5 to

3.0ohms for the 12 volt heater assembly and 6.0 to

9.0ohms for the 24 volt heater assembly. Warm the thermostat and heater assembly to approximately 90 degrees Fahrenheit and again check the resistance. The resistance should exceed 1000 ohms. If the resistance values obtained are within the stated limits, the thermostat and heater assembly is operating properly. If the resistance values obtained are outside the stated limits, replace the heater and thermostat assembly.

HEATER & THERMOSTAT

CONNECTOR

FIGURE 3 - AD-IS®AIR DRYER HEATER AND

THERMOSTAT CONNECTOR

REBUILDING THE AD-IS®AIR DRYER

GENERAL SAFETY GUIDELINES

WARNING! PLEASE READ AND FOLLOW THESE INSTRUCTIONS TO AVOID PERSONAL INJURY OR DEATH:

When working on or around a vehicle, the following general precautions should be observed at all times.

1.Park the vehicle on a level surface, apply the parking brakes, and always block the wheels. Always wear safety glasses.

2.Stop the engine and remove ignition key when working under or around the vehicle. When

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