How to judge whether a HYDAC filter element needs to be replaced?

I. Check the Differential Pressure Indicator (Most Standard and Accurate)

Most hydraulic filters are equipped with a differential pressure transmitter or clogging indicator light.

If the indicator turns red or the transmitter gives an alarm:

Judgment: Replacement is required immediately.

Standard critical value:

A HYDAC filter element is considered clogged when the differential pressure reaches 0.5～0.8 MPa. Delayed replacement will cause pump cavitation, valve sticking, and system overpressure.

II. Check Equipment Operating Status (Judgment Without Instruments)

Replace the filter element immediately if any of the following occurs:

Unstable hydraulic pressure, slow operation, and weak cylinder output

Abnormally rising oil temperature

Unusual noise from the hydraulic pump or humming cavitation sound

Frequent sticking and lagging of directional valves and proportional valves

Principle: Clogged filter → poor oil flow → insufficient flow, temperature rise, and increased pump load.

III. Check Hydraulic Oil Condition

Oil turns black, turbid, or contains metal particles

Oil emulsifies and turns milky due to water ingress

Significant increase of sediment at the tank bottom

Once the oil quality deteriorates, replace the filter element regardless of service time to avoid secondary system contamination.

IV. Judge by Service Cycle (Maintenance Backup Standard)

Clean conditions (hydraulic stations, wind power, equipment rooms): Replace every 1500～2000 hours

Ordinary factory conditions: Replace every 800～1200 hours

Severe dusty conditions (mining, construction machinery): Replace every 300～500 hours