BENDIX BW1948 manual Operation & Leakage Tests Also see Video BW2327

4.Perform the Operation & Leakage Tests listed in this publication.

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, but reduces the effectiveness of the device to dry air. Use of other substances can damage the air dryer and may void the warranty.

OPERATION & LEAKAGE TESTS (ALSO SEE 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 cutout and note that the AD-IS®air dryer purges with an audible escape of air. Watch the system pressure and note the pressure fall-off 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. Refer to section entitled Troubleshooting, Symptoms 1 and 4.

3.Check for excessive leakage around the purge valve 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 cutout and note that the AD-IS®air dryer 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 an AD-IS®air dryer purge. If system does not follow this pattern, refer to section entitled

Troubleshooting, Symptoms 5 and 6.

5.Check the operation of the end cover heater and thermostat assembly during cold weather operation as follows:

A.Electric Power to the Dryer

With the ignition or engine kill switch in the RUN position, check for voltage to the heater and thermostat assembly using a voltmeter or testlight. 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.

HEATER & THERMOSTAT

CONNECTOR

FIGURE 4 - AD-IS®AIR DRYER HEATER AND

THERMOSTAT CONNECTOR

B.Thermostat and Heater Operation

Note: These tests are not possible except in 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 3.0 ohms for the 12 volt heater assembly and 6.0 to 9.0 ohms 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.

6.Pressure protection valves. Observe the pressure gauges of the vehicle as system pressure builds from zero. The primary gauge should rise until it reaches approximately 109 psi (±5 psi), then level off (or a momentary slight fall) as the second pressure protection valve opens supplying the secondary reservoir. When the secondary pressure gauge passes through approximately 55 (±5 psi) and then 85 psi (±5 psi) there should be an associated leveling off (or momentary slight fall) of pressure as the third and fourth pressure protection valves open. Finally both the primary and secondary gauges should reach their full pressure of approximately 130 psi (±5 psi).

If the AD-IS®air dryer does not perform within the pressure ranges as described above recheck using gauges known to be accurate. If the readings remain outside of the ranges outlined above, replace the AD-IS®air dryer. NOTE: There are no kits available for

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