WIKA switchGauge 821 Manual De Instrucciones página 12

5. Commissioning, operation
5.1.7 Temperature load
The installation of the instrument should be made in such a way that the operat-
ing temperature, also considering the effects of convection and thermal radiation,
neither exceeds nor falls below the permissible limits. Thus the instrument and the
EN
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.
5.1.8 Commissioning of pressure compensating valve
Instruments which are fitted with a pressure compensating
valve must, following installation, be vented for internal pres-
sure compensation.
Tool: Open-ended spanner SW 9
1. Remove plastic casing
2. Loosen the threaded connection above the valve body
3. Screw the valve body tight, turned through 180°, with ≤ 4.5 Nm
5.1.9 Protection of the pressure elements from overload
If the medium is subject to rapid changes in pressure, or pressure surges are ex-
pected, then these must not act directly on the pressure element. The action of the
pressure surges must be damped, for example with the fitting of a throttle section
(reduction in cross-section in the pressure channel) or through the addition of an
adjustable throttling device.
5.1.10 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.
5.1.11 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. With the installation, a con-
tinuous inclination of approx. 1:15 is recommended.
12 Operating instructions pressure gauges with switch contact models 821, 851 or 830 E
WARNING!
The actual maximum surface temperature depends not on the equip-
ment itself, but mainly on the operating conditions. With gaseous sub-
stances, the temperature 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.
Before commissioning
After commissioning