15mm and 22mm water leak detection sensors used for pipe in pipe, bunded tanks and tank overflows applications.


  • Voltage – 12 to 24V AC or 13 to 24V DC
  • Burdon – 20mA when detecting, 15mA in standby
  • Relay output – 30VAC/DC 1 amp N/O (close in Alarm) or N/C (open in Alarm) contact; please specify
  • Interconnecting lead – 3 metres long but any length can be catered for

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All of the information below is available in our PPS Pipe Probe With Output Relay Data Sheet.

web 15-22 pipe in pipe sensor

These sensors have been designed for pipe in pipe water, oil or chemical leak detection including bunded tanks or any application where monitoring of an internal bunded area is required.

The sensors fit all 15mm or 22mm plastic fittings and have been designed to detect the presents of any liquid including water, fuel oil etc. and energise an internal relay to provide a signal to existing alarm systems, Building Management Systems or SMS messaging systems.

The mode of operation is the principle of total internal reflection. An LED and photo-transistor are housed in a plastic (Polysulfone) dome. When no liquid is present, light from the LED is internally reflected from the dome to the phototransistor.

When a liquid covers the dome, the effective refractive index at the dome oil boundary changes allowing some light from the LED to escape. Thus the amount of light received by the photo-transistor is reduced indicating the presents of a liquid.

Sensors can be connected together to give a common alarm within an area or connected individually to provided exact location of a leak.


  • Housing type – ABS Plastic
  • Size – 15mm
  • Colour – Grey
  • Input power – 12 to 24 VAC or DC
  • Power Consumption – 0.84W@ 27.1VAC, 0.5W@ 24VDC
  • Connections to Sensor – 3 metre long 4 core signal cable
  • Relay contact – Normally Open , (close in alarm ) 1 amp 30VDC volt free contact

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