CARRIER-PLANETARY 3P1609 - Caterpillar

The service indicator is mounted on the tube that leads from the engine air cleaner to the turbocharger inlet.
Illustration 1 g01174131
(1) Service Indicator Screen Inspect and Clean the Indicator
Inspect the service indicator. Clean the air cleaner element or replace the element when the following conditions occur:
The screen on the service indicator becomes red.
Restriction of the air flowing through the air filter reaches 635 58.4 mm (25 2.3 inch)H2O.
The service indicator has one or more of the following:
Cracks
Holes
Loose fittingsTest the Service Indicator
Service indicators are important instruments. Test the service indicator by using one of the following methods.
Push the plunger into the element in order to reset. If the service indicator does not reset in three pushes or less, replace the service indicator.
The following method can only be used when the air cleaner has been used. This test will not work immediately after cleaning the air cleaner. Push the plunger into the element. Start the engine. If the plunger does not move, replace the service indicator.The service indicator may require frequent replacement in environments that are severely dusty. Replace the service indicator at the end of each year if the service indicator has not been replaced during the year. Replace the service indicator when the engine is overhauled. Replace the service indicator whenever major engine components are replaced.