WIKA 851.02.100 - Manual (Page 9)

9 WIKA Operating instructions DELTA-plus, DELTA-comb and DELTA-switch per ATEX
11242370 06/2007 GB/D/F
GB
8. Optional extras / accessories
8.1 Integrated pressure equalising valve
The zero point check during operation
is enabled by pushing the valve
button.
The measuring medium flows
from the higher pressure side to the
opposite side and the differential
pressure drops to zero.
st and sv:
When the valve button is pushed, the differential pressure pointer must move
into the range of the zero point tolerance bar. If it does, the instrument is
functioning correctly. In the case of possible deviations beyond the tolerance
bar, a zero point correction can be made via a standard integrated adjustment
pointer.
To do this, the snap-fit window must be lifted
off using a screw driver at the impression/recess
in the circumference.
The zero point is corrected by turning the slotted
screw on the adjustment pointer.
Afterwards the window must be snap-fitted back
onto the case. The differential pressure is indicated
once more, as soon as the valve button is released.
8. Optional extras / accessories
Slotted
screw
Differential pressure
is zero
Differential pressure
is measured again
Released
Valve button,
pushed