PDE – Differential pressure switch – Clogging indicator

Differential pressure switch

A pressure switch is defined as “differential” because it does not monitor individual pressure levels but rather the difference between two distinct pressure values. When the difference between P2 and P1 exceeds a certain predetermined range, the pressure switch activates.

Where is a differential pressure switch applied?

Differential pressure switches (PDE) are used to monitor the degree of clogging in a hydraulic filter. If the filter is not clogged, the pressure upstream and downstream is almost identical, while with a clogged filter, there will be a rise in downstream pressure, sufficient to activate the pressure switch. This, thanks to an indicator that changes color from green to red, will signal (visually as well as electrically) the anomaly.

Differential pressure switch with clogging indicator

All our differential pressure switches are equipped with clogging indicators: signaling devices that visually indicate when the switch has activated. In addition to visual signaling, the pressure switch also provides an electrical signal, allowing timely intervention for filter maintenance.

What is the purpose of the clogging indicator in pressure switches?

It is useful for knowing when to replace the filter element because it is clogging. The device monitors the fluid pressure upstream and downstream of the hydraulic filter and alerts when the two pressures start to differ.


  • Continuous monitoring of the filter element condition
  • Precise indication of the filter’s efficiency status
  • Optimization of filter element replacements
  • Prevention of potential system contamination
  • Reduction of unexpected machine downtime
  • Reduction of hydraulic component repair interventions due to compromised fluid performance in the system


Switch rating 1 A / 220 Vac – 3 A / 24 Vdc – 7 A / 250Vac
Electrical connection DIN 43650 – PG09 or PG11
Working range 2 bar – 5 bar – 7 bar – 10 bar
Max. static pressure 450 bar
Set point tolerance +/- 10%
Fixed differential 30% of set-point
Temperature tange -25 °C +140 °C (according to diaphragm/seal material)
Contact SPDT
Body material Brass
Diaphragm/ Seal material HNBR – FKM
Threads G1/2″ – M22 x 1.5 – M20 x 1.5
Protection IP67
Certification CE
Options Gold-plated contacts for low current  – High current microswitch