BENDIX BW1450 manual AD-4AIR Dryer Sectional View

CHECK	PURGE
VALVE	ORIFICE

	DESICCANT		PURGE VOLUME
	CARTRIDGE
			DESICCANT
				BED
CHECK VALVE			PERFORATED PLATE
ASSEMBLY
NUT			OIL SEPARATOR
				SEALING RING
WASHER				SEALING RING
				SEALING RING
END COVER				SEALING RING
				SUPPLY
SPECIAL			SPRING	PORT
WASHER			PURGE PISTON
HEX HEAD	DELIVERY
			O-RING
SCREW	PORT	EXHAUST	EXHAUST
	PURGE		COVER
		DIAPHRAGM
	VALVE
FIGURE 4 - AD-4™AIR DRYER SECTIONAL VIEW

Every 900 operating hours or 25,000 miles or every three

(3) months:

1.Check for moisture in the air brake system by opening reservoirs, drain cocks, or valves and checking for presence of water. If moisture is present, the desiccant 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. Refer to Appendix A, Table A and the column entitled Vehicle Vocation.

C.The air dryer has been installed in a system that has been previously used without an air dryer. This type system will be saturated with moisture and several weeks of operation may be required to dry it out.

D.Location of the air dryer is too close to the air compressor. Refer to Locating AD-4™Air Dryer On Vehicle section and Appendix A, Table A, column 2 for discharge line length.

E.In areas where more than a 30 degree range of temperature occurs in one day, small amounts of water can accumulate in the air brake system due to condensation. Under these conditions, the presence of small amounts of moisture is normal and should not be considered as an indication that the dryer is not performing properly.

Note: A small amount of oil in the system may be normal and should not, in itself, be considered a reason to replace the desiccant; oil stained desiccant can function adequately.

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