TB 9-4931-228-24
MARSH, TYPES 2 AND 3
6. Preliminary Instructions
a. The instructions outlined in paragraphs 6 and 7 are preparatory to the calibration
process. Personnel should become familiar with the applicable sections before beginning
the calibration.
b. Items of equipment used in this procedure are referenced within the text by common
c. Unless otherwise specified, verify the result of each test and, whenever the test
requirement is not met, take corrective action before continuing with the calibration.
Adjustments required to calibrate the TI are included in this procedure. Additional
maintenance information is contained in the manufacturer's manual for this TI.
d. Unless otherwise specified, all controls and control settings refer to the TI.
WARNING
To prevent injury to personnel or damage to equipment, make
certain that all components are within the range of the unit to
be calibrated and all connections are securely sealed prior to
applying pressure to TI. Never attempt to tighten connections
with pressure applied. Close all valves, and vent all pressure
lines before disconnecting equipment.
WARNING
Always use digital pressure controller control mode to reduce
system pressure. Using the vent function to reduce pressure
may damage rate-sensitive equipment. Only use vent function
when system pressure is close to local atmospheric pressure.
Local atmospheric pressure may vary, but the value should be
0 psi gage; approximately 29.7 inHg or 14.7 psi absolute.
NOTE
Zero
digital
pressure
controller
before
performing
measurements.
a. Energize digital pressure controller and allow 30 minutes for warm-up.