15
Series 275 Convectron Gauge Bridge Amp PC Board
Instruction Manual - 275331
Chapter 3
3
Installation
3.1 Install the Convectron Gauge
For proper operation above about 1 Torr, install Convectron gauges with the gauge axis horizontal.
To minimize pressure indication errors, avoid installing the Convectron gauge where it will vibrate.
Vibration causes convection cooling of the sensor and will cause the pressure indication to be high.
For proper operation of the module above 1 Torr, orient the module so the axis is horizontal (see
Figure 3-1). Although the Convectron gauge will read correctly below 1 Torr with the module
mounted in any position, inaccurate readings will result at pressures above 1 Torr if the module axis
is not horizontal.
3.1.1 Mounting Options
• Compression Mount/Quick Connect
Do not use for positive pressure applications. The gauge may be forcefully ejected.
The gauge port is designed to fit a standard 1/2 in. compression/quick connect mounting such
as an Ultra-Torr fitting.
Remove the caplug from the gauge tube port, insert the gauge tube port into the compression
fitting and finger tighten the press ring. If a seal is not achieved it may be due to extreme
cleanliness of the O-ring. A light film of vacuum grease will ensure sealing and is normally
preferable to the use of pliers or pipe wrench to further tighten the press ring. You may point
the electrical pins of the gauge tube anywhere you wish in a 360° horizontal circle for
optimum routing of the gauge tube cable.
• 1/8 NPT Mount
Fits standard 1/8 NPT female fitting. Wrap the threads of the gauge port with thread seal tape
and hand tighten. Do not use a wrench or tool. Tighten only sufficiently to achieve a seal.
• VCR/VCO Mount
Remove the plastic or metal bead protector cap from the bead. When using gasket, place it
into the female nut where applicable. Assemble components and snug finger-tight. While
holding a backup wrench stationary, tighten the female nut 1/8 turn past finger-tight for 316
stainless steel and nickel gaskets; or 1/4 turn past finger-tight for copper and aluminum gaskets.
• NW10KF, NW16KF, NW25KF and NW40KF Flange Mount
The KF mounting system requires an O-ring and centering ring to be placed between the
mating flanges. The flanges are then held together with the aluminum flange clamp by
tightening the wing nut. Maximum pressure for this style mounting system is 1000 Torr
absolute.
• ConFlat Flange Mount
To minimize possibility of leaks with ConFlat flanges, use high strength stainless steel bolts and
a new, clean OFHC copper gasket. Avoid scratching the seal surfaces. To avoid contamination,
do not use nonmetal gaskets.
After finger tightening all bolts, continue tightening about 1/8 turn in crisscross order, e.g., 1,
4, 2, 5, 3, 6, 4 . . . until the flanges are in contact. After contact, further tighten each bolt about
1/16 turn.