close to isolate the instruments from the pump.
This safety relief system has been properly
set at the factory. In the event minor adjustment of the safety relief system is required,
proceed as follows:
1 . Prepare test set for use in accordance with procedure given in paragraph 2-3.
2. Release 10 captive fasteners and remove bottom front panel of test-set to gain
access to bellows block assembly.
3. Place appropriate instrument under vacuum or pressure, depending upon which
bellows is to be adjusted.
Refer to paragraph 2-5 for operating procedure. Adjust test
set until instrument shows maximum indication.
4. Refer to figure 3-1 to identify bellows to be adjusted; markings on front of bellows
block assembly identify each bellows assembly and the instrument system which it protects.
Refer to table 2-1 for safety relief point settings.
5. Loosen locking nut (figure 3-1) and turn adjustment screw until associated micro-
switch is actuated and solenoid valves. are heard to operate at required safety relief point.
Turn vacuum bellows adjustment screw clockwise to decrease and counterclockwise to
increase the vacuum at which microswitch is actuated.
Turn pressure bellows adjustment
screw counterclockwise to decrease and clockwise to increase the pressure at which micro-
switch is actuated.
6. Tighten locking nut on adjustment screw or screws which was reset, being careful
not to disturb setting of adjustment screw.
7. Turn off test set in accordance with procedure given in paragraph 3-7.
8. Replace bottom front panel of test set and secure 10 captive fasteners.
3-9. TROUBLESHOOTING.
3-10. If there is insufficient vacuum or pressure for maximum indications on the test set
instruments, it is necessary to determine whether the pump is at fault or a leak exists in the
3-4