Differential relief valves

Differential pressure control valve

Differential relief valves work independently and are used in systems with low or medium power boilers, whatever type of valves are fitted (manual or thermostatic).

Their job is to automatically deliver a constant flow rate within the circuit, protect the pump and avoid the acoustic effects associated with overpressure.

Differential relief valves benefits

  • Ready to install (factory pre-set to 0.2 bar)
  • Energy savings
  • Adjustment using easy-to-read rotating ring
  • Transparent cover to lock the setting while keeping it readable
  • Extends the life of boilers.

Differential relief valves applications

When taps are closed, the pressure rises in the system.

The differential relief valve, fitted on a by-pass between the supply and return pipe, prevents this rise in differential pressure in the system.


Model 872 B, flat seal
3/4" x 3/4"


Model 872 B, compression
DN22 X DN22


  • Flow rate:   50 to 2000 L/h
  • Max. differential pressure: 0,6 bar
  • Max temperature:  120°C
  • Min temperature:  -10°C
  • Range of adjustment:  0.1 to 0.5 bar