3 Installation
25
Series 340 Vacuum Gauge Controller
Instruction Manual - 340005 - Rev. D
The following precautions in the use and installation of the Convectron gauge must be observed.
1.
Observe the precautions in this chapter regarding gauge mounting position and high pressure
operation.
2.
The gauge should be installed with the port oriented vertically downward to ensure that no
system condensates or other liquids collect in the gauge tube.
3.
Keep the gauge clean. Do not remove the mounting port cover until you are ready to install the
gauge tube.
4.
Do not mount the gauge in a manner such that deposition of process vapors upon the internal
surfaces of the gauge may occur through line-of-sight access to the interior of the gauge.
5.
Do not install the gauge where high amplitudes of vibration are present. Excessive vibration
will cause forced convection at high pressure giving erroneous readings.
6.
Do not bake the gauge to temperatures above 150 ºC.
7.
Do not install the gauge where it will be exposed to corrosive gases such as mercury vapor,
chlorine, or fluorine, which will attack the gold plated sensor.
8.
For greatest accuracy and repeatability the gauge should be located in a stable room
temperature environment.
3.3.2 Gauge Orientation
It is important to consider the orientation of the gauge if accurate readings above 1 Torr are desired.
Below 1 Torr: The gauge will operate and accurately measure pressure below 1 Torr when mounted
in any orientation.
Above 1 Torr: The gauge will accurately measure pressures above 1 Torr only when mounted with
its axis horizontal, preferably with the port pointing vertically downward, as shown in Figure 3-7. It
is valuable to point the port downward to facilitate the removal of condensation and other
contaminants.
Furthermore, the gauge is factory calibrated with the port pointing vertically downward. Installation
of the gauge with the port in other orientations may affect the accuracy of the indicated pressure.
Mounting clearance dimensions are shown in Figure 3-7.
If the gauge becomes disconnected from the controller or if the sensor wire in the
gauge fails, the controller will indicate a voltage equal to above atmosphere.
The calibration of the gauge will be seriously affected by any gas which will attack
the gold plated sensor, and could result in overpressurizing the system. Two primary
gases in this category are mercury vapor and fluorine.
