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Instruction Manual
Service
Calibration
Every InstruTech module is calibrated prior to shipment using Nitrogen. However, you can adjust the zero and
span, using the procedure described above. Zero and span settings affect the displayed value and the output
signal. Care should be exercised when using gases other than nitrogen N
information.
Maintenance
Under normal circumstances, there is no maintenance required for your InstruTech module. Good manufacturing
practice suggests the unit should be periodically calibrated against known calibration standards.
Cleaning
The most common cause of all vacuum gauge failures is contamination of the sensor. Contamination can be
generally characterized as either a reaction of process gases with sensor elements, or an accumulation of
material on the sensor elements. Sensors that fail due to chemical reaction are generally not salvageable.
Sensors that fail due to coating may possibly be restored by cleaning. See Appendix C for a more complete
discussion of contamination and cleaning procedures.
Troubleshooting
Indication
Display is off / blank
Readings appear very different
from expected pressure
Readings are noisy or erratic
Gauge cannot be calibrated - zero
and span (vacuum & atm)
Setpoint does not actuate
InstruTech, Inc
InstruTech CVM-211 "Stinger" Convection Vacuum Gauge Module
Possible Cause
No power
The process gas is different from
the gas used to calibrate the CVM.
Module has not been calibrated or
has been calibrated incorrectly
Loose cables or connections
Contamination
Contamination.
Sensor failure for other cause.
Incorrect setup
- See Appendix B for more
2
Possible Solution
Check cable connections and verify
that power is being supplied.
Correct readings for different gas
thermal conductivity.
See Appendix B.
Check that zero and span (atm) are
adjusted correctly.
Check and tighten connections.
Inspect gauge for signs of
contamination such as particles,
deposits, or discoloration on gauge
inlet. Try cleaning if appropriate.
See section below on cleaning.
Replace CVM module.
Check setpoint setup
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