Service Indicators for Construction Equipment

Maintenance Indicators for Suction, Return and Pressure Filters

• Differential pressure indicators: installed in return and pressure filters to monitor pressure drop across the element
• Vacuum indicators: positioned on the suction side in suction filters and lines
• Pressure indicators: for pressure-side applications within the respective assembly
• Electrical maintenance switches: provide a signal at defined switching pressure
• Combined indicators: visual indication and electrical signal in one unit

Key factors are filter position and assembly as well as switching pressure, connection and installation setup.

Differential pressure indicators belong to return and pressure filters. Vacuum indicators are used in suction filters.

Switching Pressure and System Matching

Typical switching pressures vary depending on design, commonly around 1.3 bar, 2.7 bar, 5 bar or 8 bar.

The switching pressure is set below the bypass threshold of the assembly. Incorrect values shift the service interval or result in unreliable indication.

Design and Signal Type

Visual indicators provide direct on-unit status. Electrical switches trigger a signal to the machine or control system. Combined units integrate both functions.

Designs differ in signal path, connection layout and construction and are not interchangeable.

Assignment by Filter Position

Differential pressure indicators are installed in return and pressure filter assemblies. Vacuum indicators belong to suction-side monitoring.

The actual installation position within the hydraulic system is decisive.

Typical Mismatches in Practice

• Switching pressure: incorrect value – service interval too early or too late
• Filter position: wrong indicator type selected
• Design: not compatible with the existing assembly
• Connection: thread or installation layout does not match

Mismatches become visible through incorrect switching points, missing signals or installation issues.

Maintenance Indicators within Hydraulic Filter Accessories

Maintenance indicators are part of the hydraulic filter accessories and are directly integrated into hydraulic filters.

Related components in this cluster include level gauges and filter heads.

Maintenance indicators are installed in suction filters, return filters and pressure filters and operate in direct relation to hydraulic filter elements.

Check Before Ordering

• Reference number
• Filter position
• Switching pressure
• Type (visual / electrical / combined)
• Connection and installation setup