Service And Maintenance - WIKA PGT23.100 Betriebsanleitung

9. Service and maintenance

9. Service and maintenance
Always open isolating devices gently, never abruptly, since this may generate
sudden pressure surges that may damage the gauge. The maximum working
pressure for pressure gauges with transmitters is indicated by the limit marks on
the dial.
With fluctuating pressure loads, lower values apply in accordance with EN 837.
The pressure gauges with transmitters require no maintenance and feature a
long service life if handled and operated properly. As a result of the mechanical
loading, and depending on the service conditions, it may become necessary to
check and readjust the zero point of the transmitter.
Zero point test
Normally the zero point is checked and adjusted in an unpressurised state.
For measuring ranges whose scale does not start at atmospheric pressure
the pressure gauge must be pressurised with the pressure value of the scale
start. The zero point of differential pressure gauges with transmitters should be
checked and adjusted by opening the pressure compensating valve under static
load.
Mechanical zero point (pointer)
If the pointer deviates from the zero point (in the unpressur-
ised condition), the zero point may be corrected by means
of the integrated adjustable pointer. To do this, remove
the bayonet ring, including the window and seal, from the
housing. The zero point is altered by turning the adjusting
screw on the adjustable pointer.
After correcting the zero point, fasten the bayonet ring
and the window with its seal and then close the pressure
compensating valve or open the stop valve.
Electrical zero point (4 mA)
If the mechanical zero point has been altered via the adjustable pointer, the
electrical zero point must be matched to the mechanical one. To do this, apply
the pressure value of the scale start. The scale start corresponds to the smallest
electrical signal (depending on the variant either 0 mA, 4 mA or 0 V).
Loosen the complete cable hood on the right-hand side of the pressure gauge by
completely unscrewing the screw  on the top of the cable hood cover  using
an appropriate screwdriver (0.6 x 3.5 mm).
WIKA Operating Instructions intelliGAUGE family
1)
Slotted
screw
17
EN