Agilent Technologies FRG700KF25 Operating Instructions Manual page 12

Inverted Magnetron Pirani Gauge FRG-700 FRG-702
Procedure
The gauge may be mounted in any orientation. To keep condensates
and particles from getting into the measuring chamber preferably
choose a horizontal to upright position and possibly use a seal with a
centering ring and filter.
If adjustment should be possible after the gauge has been installed, be
sure to install it so that the <HV> and <ATM> trimmer potentiometers
can be accessed with a screw driver (  18).
When making a CF flange connection, it may be advantageous to
temporarily remove the electronics and the magnet unit (  13).
Remove the protective lid and connect the product to the vacuum system.
Seal with centering ring
Keep the protective lid.
12
or
Clamp Seal with centering
ring and filter
Protective lid