P
P
a
a
g
g
e
e
8
8
o
o
f
f
2
2
4
4.4. PUMP SAFETY VALVE
NOTE: The internal safety valve of the pump has been designed to protect the pump against an excessive pressure and
it must not be used as a control valve of the system pressure.
The volatile liquid pumping in adverse suction conditions can cause cavitation. The partial closing of the discharge
valve will cause vibrations to the internal safety valve, that is why is not recommended. For this type of use, install
an external control valve of the system pressure and the required bypass up to the storage tank.
It is also advisable to install a control valve of the system pressure when the pump is going to work during periods
longer than 1 minute with the discharge valve closed.
4.4.1. Safety valve setting
The value of the safety valve setting set in factory it is marked in the metallic sheet in the valve cover.
It is advisable to adjust the safety valve as minimum 10-20 psi (69-138 kPa) above the working pressure or the
value of the control valve setting of the system pressure.
Safety valve setting instructions:
1.
To increase the value of the pressure setting:
Disassemble the cap of the valve (no. 17) and the gasket.
Loosen the nut, if there is any.
Turn the tensor stud (no. 9) inwards or clockwise.
Check the gasket and replace it if required.
Reassemble the gasket and the cap of the safety valve.
2.
To reduce the value of the pressure setting:
Disassemble the cap of the valve (no. 17) and the gasket.
Loosen the nut, if there is any.
Turn the tensor stud (no. 9) outwards or anticlockwise.
Check the gasket and replace it if required.
Reassemble the gasket and the cap of the safety valve.
The cap of the safety valve is exposed to the pumping fluid and may contain some fo
this fluid.
An incorrect setting of the safety valve can cause the breaking of some system
components, injury to people or damages to property.
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