phone: (215) 947-2500 fax: (215) 947-7464 e-mail:[email protected] web site: www.televac.com
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CHAPTER 7
CHAPTER 8
Maintenance
No maintenance is required beyond periodic replacement of a contaminated sensor. To replace the
sensor, remove the Philips head screw in the center of the instrument, then gently rock and pull off the
electronic assembly. Replace the old sensor with a new one, remount the electronics and replace the
Phillips head screw.
DO NOT OVER TIGHTEN THE SCREW!
Adjust the “ATM” screw for the proper
reading when the vacuum system is vented.
Calibration
All instrumentation is calibrated at the factory. No further calibration at the customer’s facility should be
required, unless the gauge tube is replaced. In this instance the “ATM” adjustment should be done. No re-
adjustment of the zero should be required unless it has been changed.
For a reliable recalibration at a later date, it is necessary to have a reference standard vacuum system
whose pressure is known to be accurate. For such a calibration, the instrument, sensor tube and cable
should be returned to the factory for re-certification. However, if the vacuum calibration verification must
be done at the customer’s facility, a knowledgeable electronics technician trained in vacuum calibration
should operate equipment of certifiable accuracy.
Troubleshooting
1. If display consistently displays “HI”, the atmosphere adjustment may be incorrect or there may be a
broken filament in the sensor. If a broken filament is suspected, check for continuity between pins # 4 &
# 8 and # 2 & # 6 on the sensor.
2. If the display constantly reads “LO”, the sensor may have become inoperative. Check for correct
reassembly after bake out.
NOTE: If, after doing some or all of the above, the units are still inoperative, return to the factory for
repair.
CHAPTER 6
TELEVAC
