TB 9-4931-228-24
d. Observe TI scale, if TI does not indicate zero, adjust recalibration screw to obtain
zero indication.
e. Adjust regulator to apply 10 psi to digital pressure controller +300 Supply.
f. Energize vacuum pump.
g. Operate digital pressure controller to exercise TI three times over range of 0 to 28
inHg (-28 inHg indication on digital pressure controller.)
13. Vacuum
a. Performance Check
NOTE
Operate digital pressure controller in Negative Gage mode for
these vacuum checks, i.e., enter Set points as negative
numbers.
(1) Operate digital pressure controller for TI indications listed in table 5. The digital
pressure controller will indicate within limits specified.
NOTE
Gently tap TI before each reading to reduce error due to
(2) Adjust digital pressure controller for zero indication on TI.
(3) Deenergize vacuum source.
(4) Close nitrogen tank and bleed pressure from lines using manifold bracket vent valve.
(5) Perform vent operation on digital pressure controller.
b. Adjustments. No adjustments can be made.
Table 5. Vacuum Check
Pneumatic pressure standard
Test instrument
indications (inHg)
indications
Min
Max
5
-3.5
-6.5
10
-8.5
-11.5
15
-13.5
-16.5
20
-18.5
-21.5
1
25
-23.5
-26.5
1Location
and atmospheric conditions may prohibit
calibration at this test point.
14. Pressure
a. Performance Check
(1) Remove hydraulic comparator from carrying case.