Pump Efficiency Monitor

PEM Probes

Marcor’s Pump Efficiency Monitor uses pressure measurements and state-of-the-art differential temperature measurement to accurately measure the energy wastage in a pumping system. The flow rate through the pump can be calculated by adding an input from an external power meter, thereby eliminating the need for a flow meter.


  • Accurate energy wastage measurement
  • No external flowmeter required
  • Easy to install
  • Excellent long-term stability
  • DIN rail mounted
  • Robust probe design
  • Standard industrial plant interface


  • Accuracy:
    • Energy Wastage: +1% (ISO5198 refers)
    • Flow rate:  1% (typical)
  • Power supply: +24VDC
  • Fluid temperature: 0 to 70°C
  • Ambient temperature: -40°C to 55°C
  • Plant interface: RS485 Modbus RTU


  • Reduced operating costs
  • Reduced maintenance costs
  • Improved overall process efficiency
  • Reduced greenhouse gas emissions
  • Improved pump scheduling
  • Effective asset management
  • Flow metering

Principle of operation

The first law of thermodynamics is also known as the principle of conservation of energy, which means that energy can neither be created nor destroyed. It can only change from one form to another. In application, it follows that any lost energy inside a pump is converted to heat, which is carried away by the pumped medium. This results in a temperature rise across the pump. Therefore pump efficiency can be determined by measuring the difference in temperature and pressure across the pump.

Typical installation

To measure the differential temperature and pressure across the pump, a tapping point, fitted with a 10mm (3/8”) nominal bore isolation valve, is required on either side of the pump.  This tapping point should be two pipe diameters away from the pump flanges. The temperature probes are inserted into the flow, and the pressure sensors are mounted on a T-piece, fitted to the isolation valve.