WIKA 233.50 - Manual (Page 2)

Correct sealing of pressure gauge connections with parallel threads  must be made
using suitable sealing rings, sealing washers or WIKA profile seals. The sealing of tapered
threads (e.g. NPT threads) is made by providing the thread , with additional sealing
material such as, for example, PTFE tape (EN 837-2).
The torque depends on the seal used. Connecting the gauge using a clamp socket or a
union nut is recommended, so that it is easier to orientate the gauge correctly.
When a blow-out device is fitted to a pressure gauge, it must be protected against being
blocked by debris and dirt. With safety pressure gauges (see dial symbol k) it must be
ensured that the free space behind the blow-out back is at least 15 mm.
After mounting, set the compensating valve (if available) from
CLOSE to OPEN.
Temperature effect
When the temperature of the measuring system deviates from
the reference temperature (+20 °C): max. ±0.4 %/10 K of full scale value
IP Ingress protection
Enclosing case IP 65 (EN 60529 / IEC 529)
Operating temperature
Ambient: Model 232 -40 ... +60 °C
Model 233 -20 ... +60 °C
Medium: The permissible medium temperature does not only depend on the instrument
design, but also on the ignition temperature of the surrounding gases, vapours
or dust. Both aspects have to be taken into account. For permissible maximum
medium temperatures see table 1
Attention! In the case of gaseous substances, the temperature may increase due to
compression warming. In these cases it may be necessary to throttle the rate of change
of pressure or reduce the permissible medium temperature.
Table 1: Permissible medium temperature
Sealing by
the thread 
Spanner flats
Sealing face 
Temperature class of the ambient
atmosphere (ignition temperature)
Maximum permissible medium temperature (in
the measuring system)
Models 232
(dry gauges) Models 233
(liquid-filled gauges)
T 6 (85 °C < T ≤ 100 °C) +70 °C +70 °C
T 5 (100 °C < T ≤ 135 °C) +85 °C +85 °C
T 4 (135 °C < T ≤ 200 °C) +120 °C +100 °C
T 3 (200 °C < T ≤ 300 °C) +185 °C +100 °C
T 2 (300 °C < T ≤ 450 °C) +200 °C +100 °C
T 1 (T > 450 °C) +200 °C +100 °C
The effective maximum surface temperature is not only dependant upon these instruments,
but mainly on the respective medium temperature!
Materials
Wetted parts:
Stainless steel
Movement: Stainless steel
Dial and pointer: Aluminium
Case, bezel ring: Stainless steel (model 23x.30: with blow-out back)
Window: Laminated safety glass
Installation
„ Nominal position per EN 837-1 / 9.6.7 figure 9: 90° (
⊥
)
„ Process connection lower mount (LM) or back mount (BM)
„ In order to avoid any additional heating, the instruments must not be exposed to direct
solar irradiation while in operation!
„ Pressure gauges must be earthed via the process connection!
Permissible ambient and operating temperatures
When mounting the pressure gauge it must be ensured that, taking into consideration the
influence of convection and heat radiation, no deviation above or below the permissible
ambient and medium temperatures can occur. The influence of temperature on the display
accuracy must be observed.