The life of an air-dryer cartridge depends on operating conditions far more than on mileage. Running the same vehicle on a humid coastal route versus a dry inland region markedly changes how fast the cartridge saturates.
What to watch
How long the compressor stays engaged is the most direct indicator of how much air the cartridge is processing. A frequently cycling compressor wears the cartridge out quickly, regardless of the calendar.
Water coming from the tank's bottom drain is the clearest sign that the dryer is no longer doing its job. The moment water appears at the drain, a replacement should be scheduled without waiting for the interval.
If the pressure build-up time has grown longer, both the compressor and the dryer side should be assessed together.
Practical approach
Instead of a fixed mileage, grouping the fleet by the route it runs and setting a separate interval for each group gives more accurate results. Shorter intervals can be used on humid routes and longer ones on dry routes.
This is sample content; it can be edited from the panel.
