Chapter 6. Testing and Fault Finding
64 | ADTS 405 R/F Mk2 Instruction Manual-English
© 2017 General Electric Company – All Rights Reserved.
f.
At the end of the “Timing” period, the display shows the rate of change of Ps, Qc and
Pt with a “T” to indicate timed average.
g.
Check that the Ps, Qc and Pt rates are less than or equal to ±0.5 mbar/min. If the leak
rate is not achieved, allow further thermal stabilization time and re-test by pressing
RATE TIMER
and selecting [WAIT 05:00], [TIME 01:00].
h.
Press
CLEAR/QUIT
to exit rate display.
6.8.3 Vacuum Leak Check
This check confirms that the unit does not leak under vacuum conditions:
a.
Press
LEAK MEASURE/CONTROL
to enter control mode. The display shows “Aim” in
place of “Leak Measure”.
b.
Enter a Ps aim of 100 mbar by pressing:
ALT/Ps, 1, 0, 0, ENTER
.
c.
Enter a Qc aim of 0 mbar by pressing:
SPEED/Qc, 0, ENTER
.
d.
Wait the required time for temperature stabilization e.g, 1 minute.
e.
Press
LEAK MEASURE/CONTROL
return to Leak Measure mode.
f.
Press
RATE TIMER
and select [WAIT 05:00], [TIME 01:00]. Observe that the “Waiting”
time is shown on the display as it counts down, followed by the “Timing” time.
g.
At the end of the “Timing” period, press
ROC/Ps RATE
to display the measured rate of
change of Ps (“T” is shown after the value indicating a timed average).
h.
Check that the Ps, Qc and Pt rates are less than or equal to ±0.5 mbar/min. If the leak
rate is not achieved, allow further thermal stabilization time and re-test by pressing
RATE TIMER
and selecting [WAIT 05:00], [TIME 01:00].
i.
Press
CLEAR/QUIT
to exit special rate time display.
6.8.4 Range Check
Using key presses based on the pressure and vacuum leak checks, control the Ps and Qc
pressures to the normal limits of operation and make sure that these are achieved. Use
minimum Ps and zero Qc and then maximum Ps and maximum Qc.
Note:
Do not exceed the maximum Pt as shown on the front panel of the unit. Use
maximum available rates of change to minimize test times.
6.8.5 Controller Stability
This check confirms the control stability:
a.
Press
LEAK MEASURE/CONTROL
to turn the pressure controllers on. “Aim” replaces
“Leak Measure” on the display.
b.
Enter a Ps aim of 510 mbar with a rate of change of 204 mbar/min. by pressing the
following:
ALT/Ps, 5, 1, 0, ENTER, ROC Ps RATE, 2, 0, 4, ENTER
c.
Enter a Qc aim of 0 mbar with a rate of change of 204 mbar/min. by pressing the
following:
SPEED/Qc, 0, ENTER, RATE, 2, 0, 4, ENTER
