Edwards PRG20K, Instruction Manual, Page: 13 / 24

D0300020001EN - Installation
Page 7
Installation
Supplied equipment

PRG gauge head
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Securing clip for connector
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Operating instructions
Connection of the gauge head
Install the gauge head vertically, i.e. with the flange facing downwards. Dimensional drawing
see
Figure 1 . The dimensions given with a double asterisk (**) to the PRG20K - DN16CF and
PRG20KCR - NW16 gauge head. Otherwise the dimensions are the same for both gauge
heads.
The maximum permissible ambient temperature for the gauge head is 80 °C. However, at this
temperature the accuracy specified for the gauge head is no longer ensured, as the
temperature compensation is only effective up to 40 °C.
If the gauge head is subjected to strong thermal radiation, it has to be protected by a suitable
thermal screen. In the case that heat is transferred to the gauge head via the connection
cable, a section of the connection cable may be cooled by a cooling spiral.
Any contamination of the sensing cell will impair the accuracy of the pressure readings
obtained. Special care must be taken in the presence of substances which cannot be removed
by solvents.
Suitable orifice plates or bends may be employed to keep any possible sources of
contamination away from the gauge head.
Bent lines should be laid in such a way that no condensate can collect or the vacuum line
cannot become blocked.
The gauge heads are connected to the operating unit via standard gauge head cables.
For the purpose of improved resistance to interference the gauge heads have been equipped
with an additional ground connection (screw terminal) at the housing which is directly linked
to the metal housing of the sensing cell.
Standard gauge head cables are fitted with a ring terminal at each end of the cable. The ring
terminals should be connected to the ground connection (screw terminal) at the housing of
WARNING:
Do not use the PRG for safety critical applications. The PRG is not intended to be fail safe.
WARNING:
Do not use the PRG to measure the pressure of explosive of flammable gasses or mixtures.
The gauge contains a heated filament which can operate at extremely high temperatures
under fault conditions.
Note:
Do not install a vent valve in the immediate vicinity of the gauge head. Sudden changes in air
flow may result in mechanical damage to the filament.