Fluke HPMS - Manual (Page 40)

RPM4/HPMS A70M/A20M-AF OPERATION AND MAINTENANCE MANUAL
© 2007 DH Instruments, a Fluke Company Page 30
The principle of the LEAK CHECK function is the measurement of the natural decrease or
increase of pressure in a fixed volume over time. The LEAK CHECK function allows a leak
check time to be set. The total pressure change and the average rate of change over the
leak check time are calculated and displayed.
 OPERATION
To run a leak check, first set the pressure to the desired leak check pressure.
Changing the pressure in a test system causes adiabatic temperature changes in the
pressurized medium that need to have dissipated before a valid leak measurement can be made.
In general, a 0.5 to 1 minute wait before running a leak check is adequate to allow the adiabatic
temperature change to dissipate and valid leak measurements to be made. However, stabilization
time may be much longer for large pressure changes and as volume and pressure increases.
To access the LEAK CHECK function, press [LEAK CHECK] from the MAIN RUN screen.
Select <1run> to run a leak test. The display is:
1. Edit field for the time over which the leak rate will be
determined, in seconds.
Set leak check time:
15 s
Edit the leak check time if desired (minimum 1, maximum 999 seconds) and press [ENT].
Press [ENT] again when ready to start the leak test. The leak test display is:
1. Standard MAIN RUN screen first line showing measured
pressure.
2. Active Q-RPT position indicator
3. Indication that leak test is running and countdown of time
remaining.
4566.8 psi g Hi
Leak testing 13 s
[ESC] can be used to abort the running leak test. [ENT] while the leak test is running restarts
the leak check timer. When the leak check timer countdown has completed,
RPM4 beeps three times and the leak check results screen is displayed:
1. Total pressure change from start to finish of leak check time.
2. Indicator of Q-RPT used to run the leak check.
3. Average rate of change of pressure over the leak check
time period ( ∆P/time in seconds).
∆P - 0.12 psi g Hi
Rate 0.008 psi/sec
From the leak check results screen, press [ENT] to repeat the leak test.
Press [ESC] to return to leak check main menu and exit to the MAIN RUN screen.
To view the results of the most recently completed leak check, press <2view>. If NO leak
check data is stored (i.e., if the RPM4 has never run a leak test or a reset has cleared
previous leak test results), the results screen displays <Data NOT available> briefly and
returns to MAIN RUN screen. Press [ENT] or [ESC] to return to the MAIN RUN screen.