Table of Contents
Advertisement
2
2. PRELIMINARY TESTS
• Upon receipt of the piezometer, connect it to the readout using the wiring charts shown in
Appendix C, and check that the zero pressure reading is within 1% F.S. of the value shown
on the calibration report after due correction for barometric pressure, elevation above sea
level and temperature.
• Apply a pressure or vacuum to the piezometer and check that the readout response is
reasonable.
• Check the insulation resistance. Use an ohmmeter to measure the resistance between any
conductor and the shield. The resistance should be greater than 50 megohms.
• If an attempt is made to check the calibration, make sure that the applied pressure is accurate.
Be aware that calibrations performed by raising and lowering the piezometer inside a
borehole or well can be compromised by a displacement of the water level caused by
changing volumes of immersed cable.
Calibrations performed in this way should be done with the filter housing removed. If the filter is
left in place, be sure that it is completely saturated and that the space between filter and
transducer is filled with water. Be sure to allow sufficient time (15 to 20 minutes) for the
piezometer to reach thermal equilibrium before beginning the test.
Advertisement
Table of Contents
