WIKA 712.15.160 Betriebsanleitung Seite 16

4. Commissioning, operation
Functions of valve manifold
Shut-off of the process line without interrupting operations:
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- For instrument mounting and testing
- For protecting the instrument from impermissible overpressure load of n-times rated
pressure of the plant
Protection of the instrument against pressure surges and shocks and thus against unspec-
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EN
ified operating conditions
Instrument shutdown, for example, if measurements are only sporadically required over
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prolonged operating periods (to increase the service life of the instrument at high pressure
change frequency)
Recalibration of the differential pressure gauge (level indication)
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1. Close shut-off valves for ⊕ and ⊖ side
2. Then open pressure compensating valve, wait for a short period and close the pressure
compensating valve again
3. The pressure standard and pressure generator are connected in the plus chamber of
the measuring system via an additional G ¼ female thread.
4. In the valve manifold, remove the test connection screw on the ⊖ side
5. The plus side can now be pressurised
After completed adjustment:
- Close test connection screw again
- Remove pressure standard and pressure generator again and seal connection
- Slowly open first ⊕ shut-off valve, then ⊖ shut-off valve
M20 x 1.5 test connection for checking the measuring instrument for the working pressure.
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The pressure compensating valve allows a zero point check during operation (with the
valve open).
1. Close shut-off valves for ⊕ and ⊖ side
2. Then open the pressure compensating valve
The medium will flow from the higher pressure side to the opposite side, the differential
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pressure on the instrument falling to zero (differential pressure display must be at zero, i.e.
within the zero tolerance range, which shows that the instrument is working correctly).
In case of deviation, the zero point can be set via the adjusta-
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ble pointer installed as standard (prior to that, loosen bayonet
ring and remove window and sealing). The zero point setting is
achieved by turning the slotted screw on the adjustable pointer.
After completed zero point setting, re-fit bayonet ring plus window
and sealing and close pressure compensating valve.
For versions with integrated transmitter electronics, the electrical
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zero point must be set.
3. Close pressure compensating valve again.
4. Slowly open first ⊕ shut-off valve, then ⊖ shut-off valve.
Differential pressure gauge models 712.15.160, 732.15.160, optional for hazardous areas
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Slotted
screw