BENDIX TCH-008-041 manual Standard Style Purge Valve

Bulletin No:TCH-008-041 Page: 2 of 3

3 o-rings

Standard Style Purge

Valve

2 o-rings

Letter “U” stamped into

the body

DLU Style Purge Valve

Figure 2 - Standard and DLU Purge Valves

Selecting the Purge Valve Replacement Kit for a Bendix® AD-9™Air Dryer

When servicing your AD-9™dryer with a purge valve replacement kit, you will need to identify the type of purge valve being replaced. Removal of the purge valve from the dryer body is necessary to identify the correct maintenance kit.

First, identify whether the purge valve is a DLU style. The DLU type can easily be distinguished from the others, because the DLU type have only two o-rings on the outside of the purge valve body, rather than the standard three o-rings. For DLU purge valves, the middle o-ring seat has been removed. Additionally, AD-9™air dryers with a DLU purge valve have the letter “U” stamped on the side of the purge valve housing. Because the letter “U” is not always visible, it is best to use the number of o-ring grooves for identification. See figure 2.

If the purge valve is a standard style (not a DLU), look through the upper oval hole in the purge valve housing to view the piston. If a black band encircling the piston is visible, then the purge valve is a soft seat type. If the piston is all metal, then the purge valve is a hard seat. See figure 1 for hard and soft seat purge valves.

After the purge valve type has been identified, the next step is to identify the heater size; voltage and wattage. The electrical connector on the purge valve is color coded as shown in the Purge Valve Replacement Kits table on the following page.

Once the correct maintenance kit is identified, service the purge valve following the instructions provided in the kit for proper replacement.

Electrical Connector

Figure 3 - Voltage and Wattage

© 2006 Bendix Commercial Vehicle Systems LLC All rights reserved. 6/2006 Printed in U.S.A.