Self-acting differential pressure controllers

RCB – flanged controllers

RCBm –screwed controllers



Direct-acting differential pressure controller are used in heating and industrial systems. Designed for controlling preset differential pressure Δp between 0.2-1.6; 1-2.8; 1-3.5 or 2.5-7 bar. Compatible with cold and hot water up to 180ºC (200°C -special version, RCB), up to 150ºC (RCBm) and non-flammable gases up to 80ºC.


  • differential pressure control
  • installed on the supply or return side
  • high accuracy – maintenance-free
  • no external energy required


All differential pressure controllers are medium-controlled proportional controllers. The valve disk (3) pressure is relieved by the relief unit (4) to guarantee stable regulation. The device has two components:

  • control element (valve), including: valve housing (1), seat (2), head (3), relief unit (4), spindle (5);
  • control unit (cylinder), including: impulse lines (6) and (7), cylinder disks (8), springs (9), cylinder spindle (10), adjustment nut (11), cylinder housing (12).


Principle of operation

The medium flows from the valve chamber (A) in the flow direction indicated. High pressure control signal is transmitted to the controller chamber (B) via the impulse line (7). Low pressure control signal is transmitted to the controllerchamber (C) via the impulse line (6). The gap between the socket (2) and the head (3) depends on the differential pressure maintained between the chambers (B) and (C). The increase in regulated differential pressure over the preset value will close the head (3) until the differential pressure between the chambers (B, C) reaches the preset value at the spring (9). The differential pressure is set with an adjustment nut (11).

The valve head (3) is normally open (no power supply).


Installing controller

Controllers must be installed on horizontal lines. Flow direction must correspond to the direction of the arrow on the housing. To ensure correct operation, the rcontroller must be protected with a filter or a strainer.

Installing Self-acting differential pressure controllers

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