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General System Pressure Regulating
Introduction
The actuator (hydraulic device supplied with the system) replaces the screw on the
pilot of the PRV, a moving rod is used to control the maximum and minimum
pressures. Working operation of the pilot remains unchanged, the only difference is
that the pressure exerted on the inner spring will vary according to the instructions of
the controller.
The needle valve to the water inlet of the PRV does not need, in general, be modified.
The needle valve prevents the PRV changing position rapidly, limiting the speed of
opening and closing the valve.
The inlet pressure is restricted in the pilot before moving to the main chamber of the
PRV. Equilibrium is achieved when the flow of water entering the upstream pilot is the
same as downstream.
Hydraulics - Needle Valve
The needle valve should be adjusted so that the amount of water is not very big, so it
does not cause the rapid closure of the PRV, which could cause serious damage to
the circuit of pipes.
Hydraulics - Actuator
To set the maximum output pressure at the PRV, temporarily disconnect actuator
tubing coming from the solenoid box, to allow the actuator top at atmospheric
pressure. With the lower locknut loosened and the top of the actuator hitting the top of
the screw, screwing the actuator in the PRV pilot to increase the downstream
pressure (or unscrew to decrease pressure). Having gained the maximum desired
pressure, tighten the lower locknut.
To adjust the minimum pressure at the PRV outlet. You have to turn the top of the
actuator in the opposite direction to clockwise slowly until desired minimum pressure.
Then adjust the upper jam to set minimum pressure.
When we have the high and low pressure, it is necessary to check them to make sure
they are well tared. It is advisable to alternate between the two pressures acting on
the solenoid.
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