Excessive system leakage is evident.

1. Inspect for system leakage.
2. Repair the system.

Excessive leakage is evident in one or more of the following components:

1. Test the system for leakage at the following components:

•	The fittings

•	The safety valve in the air dryer

2. Repair or replace as needed.

The internal check valve is faulty.

1. Remove the check valve from the assembly from the end cover.
2. Apply air pressure to the delivery side of the valve.
3. Apply a soap solution at the opposite end.
4. Inspect for leakage. Permissible air leakage per single connection is 50 sccm (standard cubic centimeters per minute), which is approximately equivalent to s single 1 inch diameter soap bubble in 10 seconds.
5. If the leakage is excessive, replace the check valve.

The governor is faulty.

1. Inspect the governor for proper cut-in and cut-out pressures.
2. Inspect the governor for excessive leakage in both positions. Refer to Air Compressor and Governor Valve Diagnosis .

The compressor unloader mechanism is leaking.

1. Remove the air inlet hose and the fitting from the air compressor inlet cavity.
2. Inspect for leakage in the unloader piston while the air compressor is unloaded. Slight leakage is permissible.