When these valves leak, the compressor capacity is reduced and results in an unbalanced stage pressure. There are several symptoms which signify that an air valve is not functioning properly. A deviation from normal intercooler pressure may indicate a leaking or broken valve. A defective inlet valve above the intercooler will cause a rise in pressure in the intercooler, while a defective discharge valve below the intercooler will cause a decrease in the intercooler pressure. An unusu-ally hot valve cover is a sign of valve trouble.
Dirt is generally the cause of leaking valves.
A periodic inspection and cleaning of valves and valve passages will minimize and perhaps prevent the occurrence of air valve troubles. The frequency for cleaning valves must be determined for each installation. The air valves are easily accessible and are removed by first loosening the valve cover plates. Then the valve and valve unloader, if installed, may be lifted out. Each valve should be marked so that it may later be returned to the same opening from which it was removed.