Ensuring adequate water pressure in the installation is extremely important not only for the safety of the installation, but also for comfort of use and economic aspects.
Caleffi Hydronic Solutions has been supplying components for domestic water installations, including water pressure regulators, throughout Europe for several decades. Our offer includes several series of this type of devices, starting from the compact 533 series regulators , through the 535 series, whose design makes installation and commissioning of the installation very easy, and ending with flange versions of the 576 series. Today we will present this type of devices using the example of the 535 series regulator.
Check out Caleffi pressure regulators in the Onninen offer
How water pressure regulators work
The principle of operation is based on the balancing of two forces. The force exerted by the spring and the force of water acting on the membrane. The operation diagram during water collection is presented below (Fig. 1).
After opening the draw-off point behind the device, the pressure under the membrane decreases. The force exerted by the spring is greater than that exerted by the water acting on the membrane. The spring causes the regulating element to move downwards, and thus the water flow. The greater the water consumption, the greater the degree of opening of the regulating element (Fig. 2).
If there is no water consumption, the pressure under the membrane increases until the set value is reached, which causes the regulating element to close. We already know how this type of devices work, so it's high time to solve the riddle: what is the difference between reducers and pressure regulators? It all comes down to the design of the regulating element, which is reflected in the operation of the valve . In the case of the reducer, the structure is as shown in the figure below (Fig. 3).
Check out Caleffi pressure regulators in the Onninen offer
The input pressure acts on the regulating element only in one direction, which has a direct impact on the operation of the spring. In such a case, a change in the inlet pressure will cause a change in the pressure after the reducer. The design of the regulator looks slightly different (Fig. 4).
The input pressure acts on the regulating element in two directions. The surfaces in the upper and lower parts are the same, which compensates for the pressure and does not affect the operation of the spring. The water regulator is resistant to fluctuations in inlet pressure. The set value is always kept at the same level.
In the case of devices from the 535 series, we are dealing with water pressure regulators . The devices in this series have been designed to streamline the installation, operation and maintenance process. All elements responsible for the operation of the regulator are placed in a removable insert, which facilitates the checking or replacement procedure (Fig. 5).
The elements of the insert containing moving parts are made of plastic with a low adhesion coefficient. This solution reduces the risk of scaling, which is the main cause of failure. The initial setting is made using a setting knob with an indicator located on both sides. The pressure setting can be made with an accuracy of 0.5 bar before or after installing the valve in the installation. The design of the regulator allows it to operate at a high inlet pressure of 25 bar.
