Overpressure - Instrutech VGC301A User Manual

Instruction Manual VGC301A Controller
CVG101 vacuum gauge tube and enclosure of the VGC301 controller must be connected directly to a good
quality earth ground. Use a ground lug on the CVG101 gauge vacuum connection / flange if necessary.
WARNING! In order to protect personnel from electric shock and bodily harm, shield all conductors which
are subject to potential high voltage electrical discharges in or around the vacuum system.
It is the user's responsibility to ensure that the electrical signals from this product and any connections made to
external devices, for example, relays and solenoids, are used in a safe manner. Always double check the system
set-up before using any signals to automate your process. Perform a hazardous operation analysis of your
system design and ensure safeguards and personnel safety measures are taken to prevent injury and property
damage

2.4 Overpressure

WARNING! Install suitable protective devices that will limit the level of pressure inside your vacuum
chamber to less than what the vacuum chamber system components are capable of withstanding. InstruTech
gauges should not be used at pressures exceeding 1000 Torr absolute pressure.
In cases where an equipment failure could cause a hazardous condition, always implement fail-safe system
operation. For example, use a pressure relief device in an automatic backfill operation where a malfunction
could result in high internal pressures if the pressure relief device was not installed on the chamber.
The CVG101 vacuum gauge tube connected to the VGC301A controller is not intended for use at pressures
above 20 psia (1000 torr); DO NOT exceed 35 psig (< 2 ½ bars) pressure inside the sensor. If your chamber goes
to higher pressures, you should install an isolation valve or pressure relief device to protect the gauge tube from
overpressure conditions. With some fittings, actual safe overpressure conditions may be lower; for example, a
quick-connect, O-ring compression fitting may forcibly release the gauge tube from the vacuum chamber fitting
with only a few psi over local uncorrected barometric (atmospheric) pressure.
CAUTION! If the internal pressure of a vacuum gauge device is allowed to increase above local
uncorrected barometric pressure (atmospheric pressure side), vacuum fittings may release and possible
overpressure conditions may cause leaks that would allow the gas inside the gauge tube to release into the
atmosphere of the surrounding environment. Toxic, pyrophoric and flammable gases are examples of
hazardous gases that if allowed to leak out of the vacuum/pressure containment vessel into the atmospheric
environment, could cause bodily injury and possible damage to equipment. Never expose the gauge tube
internal volume to pressure above local atmospheric pressure when using hazardous gases.
InstruTech, Inc.
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