Pressure reducing valve with self-contained replaceable cartridge.

Basically, we can deal with two cases. The first is contamination of the device itself. To understand why this is a problem for the regulator itself, we need to be aware of how it works. It is also worth paying attention to the pressure gauge, which shows a lower pressure than the one set on the knob. The cause is internal losses generated by the water flow.

In this case, leakage may occur. According to the principle of communicating vessels, the pressure will tend to equalize its value before and after the regulator. The device will not maintain the set pressure.

Just remove the impurities. In the case of the 535 series pressure regulators (in the drawings), this procedure is extremely simple because the regulator insert is one element that can be unscrewed with a wrench. After cleaning, the insert must be installed. There is no need to recalibrate, the pressure will be maintained according to the setting on the knob. A similar procedure can be performed for the 533 series regulators, but these require the pressure to be re-set. The second case occurs in installations where the water pressure regulator is installed in the supply of the domestic hot water tank. Unfortunately, such installation is often performed when there is no expansion vessel in the cold utility water installation. Omission of such an important element results in periodic activation of the safety valve. This happens due to the increase in pressure in the tank during water heating.

The water pressure regulator stabilizes the pressure to the set value and it remains unchanged regardless of pressure fluctuations in the water supply network. The reducer, on the other hand, reduces the pressure by a certain amount, which means that when the pressure on the water supply side changes, the pressure at the outlet of the reducer will also change.

1. Contaminants have got into the sealing area of ​​the regulator seat, which does not close properly and causes a slight leak, the pressure tends to equalize on both sides of the regulator. The situation occurs, of course, without flow, with closed draw-off points, i.e. when the regulator should be closed. 2. The pressure gauge shows the pressure of water heated in the domestic hot water tank when the regulator is installed upstream of the tank. The heated water, under the influence of thermal expansion, flows back towards the pressure regulator and the high pressure has no outlet.

In such a case, we are most likely dealing with the phenomenon of cavitation. This phenomenon occurs when we reduce the pressure from high to quite low, then the water flow speed increases rapidly between the regulator's plug and its seat, which causes the pressure to drop to the so-called evaporation pressure. Air microbubbles are then produced. When the pressure begins to increase slightly again, the bubbles rapidly implode, which in turn produces a shock wave, damaging the regulator walls, seat, seals and causing the above-mentioned noise.

NO. So let's consider this one case when we increase the setting on the Caleffi regulator:
We perform the operation in a closed flow. By turning the knob clockwise, we press the spring, which causes the plug to move downwards, allowing water to flow. Our higher pressure that we set, created at the outlet of the regulator, pushes the diaphragm even more upwards and thus balances the increased spring pressure, moves the plug up and as a result, the regulator closes again and the manometer shows our new increased pressure.