Ultimo aggiornamento: 15/11/19
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MISURE DI INGOMBRO
SELECTION
This product is intended to be incorporated on a finished machine. This product is to be utilized with clean fresh water, even slightly
additivated with normal detergents. For use involving different or corrosive liquids, contact the PA Technical department. Appropriate
filtration should be installed when using unpure liquids. Choose the valve in line with the working data of the machine where to be
installed (permissible pressure, maximum flow and rated temperature of the system). In any case, the pressure of the machine must
not exceed the
permissible pressure
imprimed on the valve.
Attention. The VB40/1000 Zero valve is sensitive to water flow: at gun opening (water flow through the valve) the system goes into
pressure, at gun closure (flow interruption) the system works at low pressure. For this reason, the VB40/1000 zero valve cannot be
installed on systems that fit always weeping antifreeze systems. Instead it can be installed on systems with antifreeze systems
weeping at low pressure. In this case it is necessary to create in the bypass line a pressure higher than the pressure at which the
antifreeze system becomes weeping.
OPERATIONS
The valve regulates the maximum pressure of the system by variating the flow discharged by the bypass. The adjustment is made by
altering, by means of a piston, the position of a sphere which closes partially the bypass opening.
The valve is sensitive to water flow. At gun opening, the water flows through the valve which maintains the system in pressure. At gun
closure, the interruption of the flow provokes the complete aperture of the bypass which allows to discharge the flow at low pressure.
At gun closure, the special mechanism of zero setting patented by PA, which does not include a check valve, keeps in connection the
delivery line and the bypass line, in that way permitting to lower the pressure all around the system and not only in the source line of
the valve.
INSTALLATION
This accessory, on a system that produces hot water, must be fitted upstream the heat generator. On a system that generates hot
water, it is advisable to fit in accessories that limit the accidental increase of fluid temperature.
Do not install the valve on the pump head
: secure the valve to the machine’s frame by means of the fixing holes obtained on the
body. In this way the valve is subject to less vibrations, reducing therefore the wearing of the internal parts. The hose from the pump to
the valve must have a minimum length of about one meter.
Always install a safety valve for protect the system.
If the nozzle wears out, the pressure decreases. To reset pressure back at work level, it is necessary to replace the worn nozzle.
When a new nozzle is fitted, re-setting of the system to its original working pressure is required.
