Goetze 810 Instrucciones De Montaje Y Mantenimiento página 9

5 Operating and Maintenance
The operating pressure of the plant is to be at least 5 % lower than the closing pressure
of the safety valve. In this way, the valve can satisfactorily close again after blowing off.
In the event of minor leaks, which may be caused by contamination between the sealing
surfaces, the valve can be made to blow off through lifting, for cleaning purposes.
In addition, by using an appropriate open-end wrench – for type 812/412 and
813/413 using a strap wrench (not a pipe wrench) – the entire upper part can be
unscrewed from the housing and any residue removed from the seat and the seat
sealing. By screwing the upper section onto the housing with subsequent tightening
the valve operates again at the set pressure.
If this does not remove the leak the sealing surface is probably damaged and this can
only be repaired at our factory or by authorized specialists.
It is recommended and also stipulated by pertinent regulations to make the safety
valve blow off from time to time through lifting, in dependence of the respective
system, in order to check the correct operation of the safety valve. They can be made
to open by hand at the latest when the working pressure is > 75% of the response
pressure.
Lifting is carried out by turning the knurled nut above the bonnet in counterclockwise
direction. Turn the knurled nut back to the stop again afterwards.
Safety valves are the ultimate safety device for the tank or system. They must be able
to prevent impermissible overpressure even when all other upstream control and moni-
toring equipment fail.
To ensure these characteristics safety valves require maintenance, just like any other
technical device.
The maintenance intervals are determined by the operator independence of the ope-
rating conditions.