TB 9-6685-330-35
NOTE
Always approach the desired scale reading from the low end of
the scale. If you exceed the desired scale reading and drop
back down to the reading, your procedure will be incorrect.
(6) After the TI readings have been recorded from the up-scale calibration check,
the TI should then be pressurized to 110 PERCENT OF FULL SCALE.
(7) From 110 PERCENT OF FULL SCALE, decrease the pressure to 100, 75, 50,
25, and 0 PERCENT OF FULL SCALE and record the DOWN-SCALE readings.
(8) This error should not exceed one-half of the specified accuracy tolerance (see
NOTE
It is suggested that when taking readings from the TI, the TI
should be lightly tapped to reduce the error that a slight
amount of friction could cause.
b. Adjustments. Refer to the manufacturers' literature and manuals. Some
differential pressure gages may be calibrated by adjusting the scale; if not, the differential
pressure gage must be replaced.
10. Final Procedure
a. Deenergize and disconnect all equipment.
b. Annotate and affix DA label/form in accordance with TB 750-25.
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