BENDIX AD-2 AIR DRYER User manual
HOLES - 4
FIGURE 1 - AD-IS
® EVERFLOW ™ ASSEMBLY, AD-IS ® AIR DRYER, AND EVERFLOW ™ ELECTRONIC MODULE
The function of the AD-IS ® EverFlow ™ assembly is to provide heavy vehicles that use large amounts of air with a dryer system that facilitates continuous fl ow drying. This assembly provides, in a single package, all the components necessary to operate two dryers. The assembly determines if high air demand is needed and continuously switches between dryers every 30 seconds until the high air demand ceases. When high air demand is not needed, the assembly uses the dryers as if in a normal braking system. Each dryer cycles as the air brake system requires. This feature prevents wasted air and unnecessary cycles. The assembly uses an electronic module that determines air demand and sequences the dryers for maximum effi ciency.
air dryer collects and removes air system contaminants in solid, liquid and vapor form before they enter the brake system. It provides clean, dry air to the components of the brake system which increases the life of the system and reduces maintenance costs. Daily manual draining of the reservoirs is eliminated, but still may be mandated by law.
The function of the pressure protection valves is to protect each reservoir from a pressure loss in the other reservoir or a pressure loss in an air accessory. Each of the pressure protection valves in the AD-IS ® air dryer may have different pressure settings, but these are factory set and must not
be changed or adjusted.
The air dryer consists of a “spin on” desiccant cartridge secured to a base assembly. The base assembly contains a delivery check valve assembly, safety valve, heater and thermostat assembly, pressure protection valves, threaded air connections and the purge valve assembly.
The removable purge valve assembly incorporates the purge valve mechanism and a turbocharger cut-off feature that is designed to prevent loss of engine “turbo” boost pressure during the purge cycle of the AD-IS
For ease of maintenance, all replaceable assemblies can be serviced without removal of the air dryer from its mounting on the vehicle. Refer to Preventive Maintenance section.
These units will not operate properly with a Holset type compressor. For discharge line unloaded compressors a three way valve must be installed upstream of the air dryer. Contact Bendix Commercial Vehicle Systems for additional information.
GENERAL (Refer to Figure 2)
assembly is designed to receive compressed air from the vehicle air compressor. It then cleans and dries the air before delivering it to the vehicle’s primary reservoir, secondary reservoir and accessories.
Additionally, the AD-IS ® EverFlow ™ assembly controls the compressor/dryer charge cycle.
AIR DRYER OPERATION:
The AD-IS ® EverFlow ™ assembly alternates between the dryers each time the brake system charges. During high air demand, the dryers alternate every 30 seconds to allow drying of the added volume of air. A pressure protection valve is needed after the dryers to maintain at least 70
PSIG at the dryers during high air demand. An electronic module monitors the air brake system and determines the amount of demand. The AD-IS ® EverFlow ™ assembly requires a signal from the delivery port of the governor into the GOV port of the EverFlow ™ electronic module. The
AD-IS ® EverFlow ™ Assembly also needs a supply air line from the secondary tank to the electronic module RES port.
This line must be 3/8 inch tubing or larger.
assembly is primarily designed to dry air on systems used for bulk unload and central tire infl ation. The system operates best when a pressure protection valve is installed between the AD-IS
™ assembly and the source of the high volume air. Refer to the system schematics, Figure 2. This pressure protection valve should have a minimum pressure of 70 PSIG.
Delivery pressure in excess of 175 PSIG can cause the purge valve to cycle rapidly between load and purge mode.
NORMAL BRAKE CYCLE
(Refer to Figure 2)
When the compressor is charging (compressing air) air fl ows through the compressor discharge line to the inlet
(1 IN) port of one of the air dryers. The compressed air includes contaminates such as oil, oil vapor, water and water vapor. The air then fl ows into the desiccant cartridge, where it fl ows through a liquid separator which collects liquids and other contaminants.
Connection Function/Connection QTY
Inlet Port (air in).
Delivery Port out (to Primary reservoir)
Delivery Port out (to Secondary reservoir)
Auxiliary Delivery Port (air out).
Auxiliary Delivery Port (air out).
Unloader Control Air (D-2A
Common Reservoir Pressure
TABLE 1 - AD-IS
® AIR DRYER PORT DESIGNATIONS
EverFlow ™ Module
Bulk Offl oad CTI
The AD-IS ® air dryer purge piston has a purge control channel drain. This allows any condensation in this area to fl ow past a diaphragm in the top of the purge piston and out through a channel in the middle of the central bolt of the purge assembly to be drained. During the purge cycle this drain is closed.
FIGURE 2 - AD-IS
® AIR DRYER SYSTEM SCHEMATIC
Air then fl ows into the desiccant drying bed and becomes progressively drier as water vapor adheres to the desiccant material in a process known as “ADSORPTION.” Dry air exits the desiccant cartridge through the delivery check valve and also through an orifi ce into the purge reservoir.
The delivery check valve opens, supplying air to pressurize the air brake system. The purge reservoir stores air that will be used to reactivate the desiccant during the purge cycle.
The air dryer will remain in the charge cycle until the air brake system pressure builds to approximately 85 p.s.i. At
85 p.s.i. the EverFlow ™ electronic module is actuated and begins the purge cycle. When the air pressure reaches approximately 106 psi, the pressure protection valves will open and air will be supplied to the primary reservoir, secondary reservoir or other accessories. If the pressure protection valves are preset to different values the valves will open in order of lowest setting to highest setting when charging a fl at system. The air dryer will remain in the charge cycle until the air brake system pressure builds to the governor cut-out setting of approximately 130 p.s.i.
When air brake system pressure reaches the cut-out setting of the governor, the governor unloads the compressor and the electronic module sends a signal to one of the air dryers to purge. The governor unloads the compressor by allowing air pressure to fi ll the line leading to the compressor unloader mechanism - causing the delivery of compressed air to the AD-IS
assembly to be suspended.
Similarly, the governor also supplies air pressure to the
™ electronic module. The electronic module uses this signal to determine the volume of air into the brake system. If the volume is normal, the electronic module sends a signal to the control port on the proper dryer. If the volume is high, the electronic module switches the dryers every 30 seconds until the air volume returns to normal.
The air dryer purge piston moves down in response to a pneumatic signal from the EverFlow ™ electronic module, causing the purge valve to open to the atmosphere and
the turbo cut-off valve to close off the supply of air from the compressor (this will be further discussed in the Turbo
Cut-off Feature section). Water and contaminants which have collected in the dryer are expelled immediately when the purge valve opens. Also, air which was fl owing through the desiccant cartridge changes direction and begins to fl ow toward the open purge valve.
Liquids and other contaminants collected by the liquid separator are removed by air fl owing from the purge reservoir through the desiccant bed to the open purge valve.
The initial purge and desiccant cartridge decompression lasts only a few seconds and is evidenced by an audible burst of air at one of the AD-IS
assembly’s purge exhaust. The actual reactivation of the desiccant bed begins as dry air from the purge reservoir fl ows through the purge orifi ce into the desiccant bed. Pressurized air from the purge reservoir expands after passing through the purge orifi ce.
The fl ow of dry air through the drying bed removes water vapor from the desiccant material. The purge lasts 30 seconds. The delivery check valve assembly prevents air pressure in the brake system from returning to the purging air dryer during the purge cycle. After the purge cycle is complete, the air dryer is ready for the next charge cycle to begin.
TURBO CUT-OFF FEATURE
The primary function of the turbo cut-off valve is to prevent loss of engine turbocharger air pressure through the AD-IS ®
assembly when both dryers are in the unloaded mode. At the onset of the purge cycle, the downward travel of the purge piston is stopped when the turbo cut-off valve
(tapered portion of purge piston with a soft seat) contacts its mating metal seat in the purge valve housing. With the turbo cut-off valve seated (closed position), air in the compressor discharge line and AD-IS
assembly inlet port cannot pass through the air dryer. In this manner the turbo cut-off effectively maintains turbo charger boost pressure to the engine. Delivery pressure in excess of 175 PSIG can
cause the purge valve to cycle rapidly between load and purge mode. All AD-IS ® EverFlow ™ Assemblies require a soft seat purge valve.
HIGH VOLUME MODE
If the GOV port of the electronic module indicates that the compressor has been charging for longer than 30 seconds, the dryers will alternatively purge every 30 seconds. This is an indication of high volume through the dryer. When the governor signal indicates the charge cycle is complete, the assembly returns to normal brake cycling.
Important: Review the warranty policy before performing any intrusive maintenance procedures. An extended warranty may be voided if intrusive maintenance is
performed during this period. Because no two vehicles operate under identical conditions, maintenance intervals will vary. Experience is a valuable guide in determining the best maintenance interval for any one particular operation.
Every 900 operating hours, or 25,000 miles or three (3) months:
1. Check for moisture in the air brake system by opening reservoir drain valves and checking for presence of water. If moisture is present, the desiccant cartridges may require replacement; however, the following conditions can also cause water accumulation and should be considered before replacing the desiccant:
A. An outside air source has been used to charge the system. This air did not pass through the drying bed.
B. Air usage is exceptionally high and not normal for a highway vehicle. This may be due to accessory air demands or some unusual air requirement that does not allow the compressor to load and unload (compressing and non-compressing cycle) in a normal fashion. Check for high air system leakage. If the vehicle vocation has changed it may be necessary to upgrade the compressor size.
C. Discharge line length too short. The minimum line length from the compressor to the dryer should be:
6' & 1/2" ID On low duty cycle applications (0-20%)
10' & 5/8" ID On high duty cycle applications (20-40%)
D. In areas where more than a 30 degree range of temperature occurs in one day, small amounts of water can temporarily accumulate in the air brake system due to condensation. Under these conditions, the presence of small amounts of moisture is normal.
1. Replace both desiccant cartridges at one time. Failure to change both could cause one dryer to pass wet air and the other dryer pass dry air. This would lead to a wet brake system.
2. A small amount of oil in the system is normal and should not be considered as a reason to replace the desiccant cartridges. Oil at the dryer purge exhaust is normal.
3. Visually check for physical damage such as chaffed or broken air and electrical lines and broken or missing parts.
4. Check the AD-IS ® EverFlow ™ assembly and purge reservoir bolts for tightness. See Figure 1. Re-torque the three air dryer bolts to 360-420 inch pounds and the four purge reservoir bolts to 300-360 inch pounds.
5. Perform the Operation & Leakage Tests listed in this publication.
6. The assembly will not operate without electrical power.
Ensure electrical power is at the assembly during vehicle operation.
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"
1. Check all lines and fi ttings 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 specifi ed, refer to section entitled Troubleshooting, Symptom 4.
4. Build up system pressure to governor cut-out and note that one of the AD-IS
assembly dryers purges with an audible burst of air, followed immediately by approximately 30 seconds of air fl owing 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
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
3.0 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.
HEATER & THERMOSTAT
FIGURE 3 - AD-IS
® AIR DRYER HEATER AND
REBUILDING THE AD-IS
GENERAL SAFETY GUIDELINES
WARNING! PLEASE READ AND FOLLOW THESE
INSTRUCTIONS TO AVOID PERSONAL INJURY
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
working in the engine compartment, the engine should be shut off and the ignition key should be removed. Where circumstances require that the engine be in operation, EXTREME CAUTION should be used to prevent personal injury resulting from contact with moving, rotating, leaking, heated or electrically charged components.
3. Do not attempt to install, remove, disassemble or assemble a component until you have read and thoroughly understand the recommended procedures. Use only the proper tools and observe all precautions pertaining to use of those tools.
4. If the work is being performed on the vehicle’s air brake system, or any auxiliary pressurized air systems, make certain to drain the air pressure from all reservoirs before beginning ANY work on the vehicle. If the vehicle is equipped with an AD-IS
air dryer system or a dryer reservoir module, be sure to drain the purge reservoir.
5. Following the vehicle manufacturer’s recommended procedures, deactivate the electrical system in a manner that safely removes all electrical power from the vehicle.
6. Never exceed manufacturer’s recommended pressures.
7. Never connect or disconnect a hose or line containing pressure; it may whip. Never remove a component or plug unless you are certain all system pressure has been depleted.
8. Use only genuine Bendix ® replacement parts, components and kits. Replacement hardware, tubing, hose, fi ttings, etc. must be of equivalent size, type and strength as original equipment and be designed specifi cally for such applications and systems.
9. Components with stripped threads or damaged parts should be replaced rather than repaired. Do not attempt repairs requiring machining or welding unless specifi cally stated and approved by the vehicle and component manufacturer.
10. Prior to returning the vehicle to service, make certain all components and systems are restored to their proper operating condition.
11. For vehicles with Antilock Traction Control (ATC), the ATC function must be disabled (ATC indicator lamp should be ON) prior to performing any vehicle maintenance where one or more wheels on a drive axle are lifted off the ground and moving.
WARNING: DO NOT ATTEMPT TO ADJUST OR SERVICE
THE PRESSURE PROTECTION VALVES. INCORRECT
PRESSURE PROTECTION VALVE SETTINGS CAN
RESULT IN THE AUTOMATIC APPLICATION OF
THE VEHICLE SPRING BRAKES WITHOUT PRIOR
See the proper service data sheet or catalog page for a full list of maintenance kits available.
NOTE: Kits are not available for the servicing of the pressure protection valves (See Figure 4). Do not attempt to adjust or service the pressure protection valves - these are not service items.
• Governor/Delivery Check Valve Kit: This kit contains the parts necessary to replace both the governor and delivery check valve.
• 12 volt or 24 volt Heater and Thermostat Kits:
Contains a replacement heater and thermostat assembly and related components required for replacement.
• Purge Valve Housing Maintenance Kit: This kit contains the parts necessary to rebuild the purge valve subassembly.
• Service New Purge Valve Housing Assembly:
Contains a service new assembly and related components to change the purge valve subassembly.
• Service New Desiccant Cartridge Kit: This kit contains the parts necessary to change the desiccant cartridge only.
• Delivery Check Valve Maintenance Kit: This kit contains the parts necessary to replace the delivery check valve.
Pressure Protection Valve Boot Replacement.
Air Dryer Replacement: Replaces the complete air dryer assembly. Includes air dryer assembly and governor.
Air Dryer Splash Shield Replacement Kit.
• Purge Reservoir Drain Valve: Replaces the drain valve on the purge reservoir.
When rebuilding or replacing components of the air dryer use only genuine Bendix
parts. For ease in servicing, the AD-IS ® air dryer has been designed so that any of the maintenance kits shown in this manual can be installed without removing the air dryer from the vehicle. CAUTION:
Always depressurize the air dryer purge reservoir, and all other reservoirs on the vehicle to 0 p.s.i. before servicing the air dryer.
If, after completing the routine operation and leakage tests, it has been determined that one or more components of the air dryer requires replacement or maintenance, refer to the previous list to fi nd the appropriate kit(s).
AND FEATURE A
IN THIS PORT
FIGURE 4- PRESSURE PROTECTION VALVE LOCATIONS
DO NOT ATTEMPT TO ADJUST OR
SERVICE THE PRESSURE PROTECTION
VALVES. INCORRECT PRESSURE
PROTECTION VALVE SETTINGS CAN
RESULT IN AUTOMATIC APPLICATION
OF VEHICLE SPRING BRAKES WITHOUT
TESTING THE AD-IS
Before placing the vehicle in service, perform the following tests.
1. Close all reservoir drain valves.
2. Build up system pressure to governor cut-out and note that one AD-IS
air dryer purges with an audible burst of air, followed immediately by approximately 30 seconds of air fl owing out of the purge valve.
3. “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 a purge at the other AD-IS
air dryer exhaust.
4. It is recommended that the total air system be tested for leakage to assure that the AD-IS
air dryer will not cycle excessively.
See Bendix publication BW5057 “Air Brake Handbook" for additional information.
BRAKING SYSTEM PROTECTION
™ assembly allows the system to maintain one brake circuit up to about 100 psi even after a pressure loss in the other brake circuit. This allows a vehicle to be moved (in an emergency), but with reduced braking capacity. Compare this to a conventional system where a loss of pressure in one service tank leaves the vehicle with a limited number of reduced braking capacity applications before the parking brakes automatically apply and stay on.
In the event of a roadside inspection the system behavior will be as follows: When the system is charged to governor cut-out, and then one reservoir drain valve is opened, initially both reservoir gauges will fall, however, the AD-IS ® EverFlow ™ assembly primary and secondary pressure protection valves will close at pressures above
70 psi, protecting the remaining brake circuit from further loss of pressure.
TEMPORARY AIR DRYER BYPASS
To temporarily bypass the EverFlow ™ assembly, the following procedure needs to be followed.
Follow the General Safety Guidelines outlined on pages
5-6 in this document.
Make sure that all residual pressure has been released and the air dryer purge reservoir has been drained to 0 p.s.i., then remove the air supply line from the compressor to the inlet port (1 IN). Remove the safety valve from the AD-IS ® air dryer body (see Figure 1 for location). Note that a short puff of trapped air may vent from the safety valve port when the valve is being removed. Install a T-fi tting into the port.
Using any adapters necessary, reinstall the safety valve in one of the branches of the T-fi tting. Using any adapters necessary, install the air supply line into the remaining
T-fi tting port. After testing the T-fi tting for any air leakage, by using a soap solution after charging to system cut-out pressure (a 1” bubble in 10 seconds is acceptable), the vehicle may be returned to temporary service.
Note: This is a temporary bypass of the air dryer, and full repair of the unit must be carried out at the earliest
opportunity. With the EverFlow ™ assembly removed from the system, contaminants will be entering the air system: reservoirs will need to be manually drained daily until the repairs are completed. At end of each working day, park vehicle and slowly drain pressure through the drain valves – leave open to the atmosphere, for several hours if possible. When repairs are carried out, be sure to check that all reservoirs (including the air dryer purge reservoir) are emptied of all contaminants.
If after bypassing the EverFlow ™ assembly the system pressure still does not build, use the following procedure to remove, clean and reinstall the delivery check valve.
DELIVERY CHECK VALVE CLEANING PROCEDURE
(Note: This is only required if system pressure does not build after temporary bypass is completed.)
Refer to Figure 6 throughout this procedure. Depressurize the air brake system following the General Safety
FIGURE 5 - SPLASH SHIELD BRACKET AND COVER - (EXPLODED VIEW)
Guidelines outlined on pages 5-6 in this document. Also, always depressurize the air dryer purge reservoir before servicing the air dryer.
This procedure does not require removal of the AD-IS
air dryer from the vehicle.
1. Remove the line from governor and mark for easy reinstallation.
2. Remove the bolts attaching the governor to the AD-IS ® air dryer and retain for reassembly.
3. Remove the governor from the air dryer. Be aware that a short puff of trapped air may vent when the governor is removed. Retain the governor gasket for reassembly if a new governor gasket is not available. Remove and retain the o-ring from the adapter.
4. The spring/delivery check valve can now be removed.
A second delivery check valve is located in the dryer without a governor. This check valve is located behind a hex head plug near the control line from the EverFlow
™ module to the air dryer. Carefully remove the hex plug and follow the instructions that follow.
5. Remove and retain the o-ring from check valve body.
CLEANING & INSPECTION
Consult the service data sheet for the dryer used in your
AD-IS ® EverFlow ™ assembly. The service data sheet contains information useful for maintenance and service of the air dryers.
1. Use a suitable solvent to clean all metal parts, and use a cotton swab to clean the bore (Note: Do not use abrasives or tools to clean the bore: any scratches caused may necessitate replacing the AD-IS ® air dryer.) Superfi cial external corrosion and/or pitting is acceptable.
2. Clean the o-rings with a clean dry cloth. Do not use solvents.
3. Inspect for physical damage to the bore and the check valve seat. If the bore is damaged (by scratches etc. that would prevent delivery check valve from seating), replace the AD-IS ® air dryer.
4. Inspect the delivery check valve, o-rings, etc. for wear or damage. Replace if necessary using the check valve replacement kit available at authorized Bendix parts outlets.
5. Inspect all air line fi ttings for corrosion and replace as necessary.
SEE NOTE 6)
130 PSI CUT-OUT)
FIGURE 6 - AD-IS
® AIR DRYER DELIVERY CHECK VALVE
1. Lubricate the smaller o-ring and check valve body with barium or silicon grease.
2. Install this o-ring on the check valve body by sliding the o-ring over the set of 4 tapered guide lands. The o-ring groove holds the o-ring in its correct location.
3. At the other end of the check valve body, the spring is installed over the set of 4 straight guide lands. When the spring has been pushed to the correct location, the check valve body is designed to hold the end of the spring in position - be sure that the spring is not loose before continuing with this installation.
4. Install the assembled check valve body/o-ring/spring in the delivery port so that the o-ring rests on its seat and the free end of the spring is visible.
5. Grease the adapter and the remaining larger o-ring and install it onto the fi tting.
6. Position gasket, insert bolts through the governor and tighten (to 125 in-lbs). (Note: Do not replace with a
standard compressor/governor gasket.)
7. Reattach line to the governor.
8. Before placing vehicle back into service, check to see that the system pressure now builds to full operational pressure.
TESTING THE EVERFLOW
ASSEMBLY AIR DRYERS
Before placing the vehicle in service, perform the following tests.
1. Close all reservoir drain valves.
2. Build up system pressure to governor cut-out and note that one of the AD-IS
Assembly air dryers purges with an audible burst of air, followed immediately by approximately 30 seconds of air fl owing out of the purge valve.
3. “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 a purge at the other AD-IS ® EverFlow ™ assembly air dryer exhaust.
4. It is recommended that the total air system be tested for leakage to assure that the AD-IS ® EverFlow ™ assembly air dryers will not cycle excessively.
See Bendix publication BW5057 “Air Brake Handbook.”
HARD SEAT SOFT SEAT
FIGURE 7- IDENTIFICATION OF HARD AND SOFT SEAT PURGE VALVES
TROUBLESHOOTING THE AD-IS ® EVERFLOW ™
Consult the service data sheet, SD-08-2418, for the dryer used in your AD-IS
assembly. The service data sheet contains information that is useful for maintenance and service of the air dryers.
1. Excessive dryer purging in the loaded cycle.
• The purge valves in both dryers must have soft-seat turbo cut-off valves. See Figure 7. Remove the purge valve an examine the upper window, replace with soft seat purge valve.
• Excessive pressure (above 175 PSIG) in the compressor discharge line. Look for obstruction downstream of the AD-IS ® EverFlow ™ assembly such as a pinched line or restrictive valve or fi tting.
2. Air dryers do not purge.
• Insuffi cient air pressure in the secondary reservoir.
The EverFlow ™ electronic module will not operate until air pressure in the secondary tank reaches 75 PSIG.
• The check valve in the AD-IS
™ supply line from the secondary tank is installed incorrectly. Refer to Figure 2.
• The fuse is blown or the air dryer is not connected to the vehicle electrical system. Check electrical connection. If the fuse is blown replace the fuse with a higher amperage fuse. The fuse must be 15 amps or higher.
• Incorrect voltage. The air dryer voltage must match the vehicle voltage. Air dryers with a white heater connector are 12 volt DC and air dryers with a grey heater connector are 24 volt DC.
3. Air brake system will not build air.
• Compressor is undersized.
Some small capacity compressors will not develop suffi cient air delivery at engine idle to allow proper operation of the AD-IS ® EverFlow ™ assembly and charge the air brake system. It may be necessary to upgrade to a compressor with a higher delivery.
4. Water in downstream reservoirs.
• Dryers not purging. See step 2 - Air dryers do not purge.
• Desiccant cartridges need to be replaced.
• No pressure protection valve installed downstream of the air dryers. Refer to Figure 2.
BW2077 © 2007 Bendix Commercial Vehicle Systems LLC All rights reserved. 10/2007 Printed in U.S.A.
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