WIKA PGT23.1 0 Serie, PGT26.1 08 Serie Betriebsanleitung Seite 16

5. Commissioning, operation
Test connection
In specific applications (e.g. steam boilers) the shut-off devices must have a test connection,
so that the instrument can be tested without being dismounted.
Temperature load
The installation of the instrument should be made in such a way that the permissible operat-
EN
ing temperature, also considering the effects of convection and thermal radiation, neither
exceeds nor falls below the permissible limits. Thus the instrument and the shut-off device
must be protected by sufficiently long measuring lines or syphons.
The influence of temperature on the indication and measurement accuracy must be
observed.
WARNING!
The actual maximum surface temperature depends not on the equipment itself,
but mainly on the operating conditions. With gaseous substances, the tempera-
ture may increase as a result of compression warming. In these cases it may be
necessary to throttle the rate of change of pressure or reduce the permissible
medium temperature.
Commissioning of pressure compensating valve
Instruments which are fitted with a pressure compensating valve
must, following installation, be vented for internal pressure compen-
sation.
Tool: Open-ended spanner SW 9
1. Remove plastic cap
2. Loosen the threaded connection above the valve body
3. Screw the valve body tight, turned through 180°, with ≤ 4.5 Nm
For information on the ingress protection, see Technical information IN 00.18
Protection of the pressure elements from overload
If the medium is subject to rapid changes in pressure, or pressure surges are expected, then
these must not act directly on the pressure element. The action of the pressure surges must
be dampened, for example with the fitting of a throttle section (reduction in cross-section in
the pressure port) or through the addition of an adjustable snubber.
Pressure tapping point
The pressure tapping point should be arranged with as large a bore as possible (≥ 6 mm)
via a shut-off device, so that the pressure tap is not distorted by a flow in the medium. The
measuring line between the pressure tapping points and the instrument should have a large
enough internal diameter to prevent blockage and lag in the pressure transmission.
Measuring line
The measuring lines must be as short as possible and should be arranged without sharp
radii in order to avoid any disruptive time lags. When routing these lines, a steady inclination
of approx. 1:15 is recommended.
16 Pressure gauges with output signal, optionally for hazardous areas
Before commissioning
After commissioning