Air Filter Restriction Switches for Construction Equipment

Function within the Air Intake System

Restriction switches monitor the load condition of the air filtration system by measuring the restriction level within the intake system. Once the defined switching point is reached, an electrical signal is transmitted to the machine control, monitoring system or indicator unit.

They do not perform any filtration function but are part of the condition-based maintenance logic of the air filter system.

Technical Variants and Switching Logic

The restriction switches in this category are primarily designed for defined restriction levels in the mbar range and differ in the following key characteristics:

• Switching point: e.g. 35 mbar, 50 mbar, 55 mbar, 60 mbar, 65 mbar, 70 mbar or 80 mbar
• Contact type: normally open (NO) or normally closed (NC)
• Design: electrical restriction switches for different system configurations
• System compatibility: matched to specific air filter and machine setups

The switching point must match the permissible restriction range of the installed air filtration system. Incorrect selection shifts the service interval and affects the operational reliability of the intake system.

Applications

• excavators and wheel loaders
• dozers and off-highway machinery
• agricultural and forestry equipment
• stationary engines and generator sets

Restriction switches are used wherever air filtration systems operate under dust load and the service condition must be electrically monitored or transmitted.

Difference Between Restriction Switches and Indicators

Restriction switches and service indicators serve the same purpose but differ in signal output. Restriction switches provide an electrical signal, while indicators display the filter condition visually.

The selection depends on machine configuration and the required type of maintenance feedback.

System Integration within Air Filter Accessories

Restriction switches are part of the air filter accessories range and are directly related to complete air filter systems and the installed air filter elements.

Within the intake system, they monitor the load condition of the downstream filter element. The use of pre-cleaners and cyclones influences the development of filter restriction by reducing dust load before the main filtration stage.

Selection Criteria

Selection is based on reference number, switching point, contact type and system configuration. Compatibility with the existing air filtration system and electrical integration is critical.

For system-specific components, reference matching is essential.

Check Before Ordering

• reference number
• switching point (mbar)
• contact type: NO or NC
• system configuration and connection type
• integration into monitoring or control system

Technical Support