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Tech-Note – Troubleshooting Internal Leaks – Type 2Valves HD


Internal Leaks

At the factory a baseline leak test is performed to verify leak-tightness and functionality. This test is a good indicator of an internal leak. The parameters are listed below.

When setting the test pressure, cap the test port before selecting the pressure field.
Running a capped port test with these parameters should yield a decay value less than 0.005psig.

Higher pressure range machines have a similar test with slightly longer fill times.

Valve manifold (removed from machine for clarity, removal of manifold is not necessary for cleaning or inspection)

The most common place for leaks to occur is at the junction of the test port fitting to the valve manifold.

Pneumatic Diagram

When the test pressure is vented, the airflow path is through Valve 1 (on) and out to atmosphere through
Valve 2 (off).

Debris from test parts or dirty air can be trapped under the piston of the 2-Way valve, holding the valve in
an open position.

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