Engineered Products has a mechanical service indicator, the Fuel Filter Minder, which provides a progressive indication of fuel-filter restriction. The indicator, designed for use on suction filters, is said to offer the benefits of attaining full use of filter capacity, reducing maintenance costs, and providing a basic diagnostic tool for troubleshooting fuel systems.
A number of installation points can be used, and the Filter Minder is supplied with fittings of the user's choice. Calibrations include 6, 8.5, 10 and 12 inches of mercury at the indicator's red zone.
According to Engineered Products (www.filterminder.com), the Fuel Filter Minder has an accuracy of ± 10 percent.