TB 9-4920-367-24
8. Vacuum
a. Performance Check
(1) Operate pneumatic pressure standard for TI indications 5 inHg absolute. The
pneumatic pressure standard will indicate between 4.75 and 5.25 inHg absolute.
(2) Repeat technique of (1) above for remaining TI indications listed in table 4.
Pneumatic pressure standard will indicate within limits specified.
NOTE
Gently tap TI before each reading to reduce error due to
Table 4. Vacuum Check
Test instrument
Pneumatic pressure standard indications
indications
(inHg absolute)
(inHg absolute)
Min
Max
10
9.75
10.25
15
14.75
15.25
20
19.75
20.25
25
24.75
25.25
29.9
29.65
30.15
(3) Adjust pneumatic pressure standard for zero indication on TI. Set pneumatic
pressure standard to measured pressure.
(4) Deenergize vacuum pump.
(5) Close nitrogen bottle valve, and bleed pressure from all lines. Perform vent
operation on pneumatic pressure standard.
b. Adjustments. No adjustments can be made.
9. Pressure
a. Performance Check
NOTE
Local atmospheric pressure may vary, but 0 psi gage (psig)
should be approximately 29.7 inHg or 14.7 psi absolute (psia).
(1) Configure pneumatic pressure standard as indicated in (a) through (d) below.
(a) Select psi units.
(b) Select Absolute mode and 315 psia range.
(c) Press Set-up button. Select User menu and zero the 315 psia range.
(d) Press Task button. Select Basic to return to Task: Basic menu.