Valve leakage is commonly caused by, but not restricted to:
- Contamination caused wear, damage, or sticking of the valve’s operating parts
- Application of air pressure to a valve’s delivery port from another device in the air system
Determine the port(s) improperly emitting air pressure and perform the following service checks:
- Exhaust port leakage at rest – Disconnect the delivery lines. If the leak stops, inspect the device at the other end of the delivery line for leakage. If the leakage continues, inspect and repair or replace the leaking valve.
- Delivery port leakage at rest – Consult the appropriate service manual for specific test procedures.
- Exhaust port leakage during application – Consult the appropriate service manual for valve specific test procedures.
Always blow out all attaching lines and reservoirs when installing a replacement valve to purge any contamination from the system. Avoid using thread sealant or tape as excess material can itself contaminate the air device.