What is the preferred tool to check the inlet restriction of a dry air filter?

The preferred tool to check the inlet restriction of a dry air filter is a food color-water filled manometer. This device is specifically designed to measure differential pressure, which is essential for assessing the restriction caused by a dirty air filter.

Using the color in the water allows technicians to see the readings more easily, making it a practical choice for workshops. A water-filled manometer works by connecting one end to the air intake system and the other end to the atmosphere. The pressure differential creates a difference in water levels that accurately indicates the restriction level.

While other tools, such as a digital manometer or pressure transducer, can also measure pressure differentials, they may not provide the ease of visibility and simplicity required for routine maintenance checks. Thus, for effective and straightforward assessment of air filter restriction, the color-water filled manometer is particularly favored.