TABLE 4. PRESSURE GAGE SCALE ERRORS

instrument panel is obvious from the exploded view,

TABLE 4. PRESSURE GAGE SCALE ERRORS

Figure 5-2. Disassembly should be limited to the removal

of those items believed to be defective or in questionable

condition.

4.5.3

INSPECTION.

Inspect the connecting tube

assemblies and all fittings for worn or damaged threads,

cracks, dents and other defects. Pay particular attention

to the flared ends of the connecting tubes as cracking is

most apt to occur at the root of the flare. Do not attempt

to reclaim a damaged connecting tube assembly by

replacing component parts. Test the pressure gages and

pressure regulators in accordance with the instructions in

paragraphs 4.5.4 through 4.5.6, following.

4.5.4 PRESSURE GAGE TESTS. Each of three pressure

gages should be checked for accuracy at least once every

100 hours of accrued compressor operating time, or

whenever their operation is questionable. The tests shall

be made by subjecting each gage to the pressures

b. Close shut-off valve. Adjust inlet pressure

specified in Table 4, first with the pressure increasing,

regulator to obtain an inlet pressure of 3000 psig. Adjust

then with the pressure decreasing. During the tests, each

handle of low pressure regulator to obtain an outlet

gage should be mounted in the normal operating position

pressure of 50 psig.

(dial face in vertical plane). Two readings should be taken

at each pressure: one before the gage is tapped, the

c. Open shut-off valve to pressurize air bottle.

second after the gage is lightly tapped. The difference of

Regulated outlet pressure shall return to, and stabilize

any two such readings (friction errors) shall not exceed

at, initial set pressure within 10 psi.

plus or minus two per cent of the full scale reading.

d. Repeat tests of steps b and c, preceding, at set

4.5.5 LOW PRESSURE REGULATOR TESTS. Test the

pressures of 100, 150 and 200 psig.

low pressure regulator in accordance with the following

procedure once every six months or whenever its

e. Close shut-off valve. Adjust inlet pressure to

operation is questionable.

3000 psig and outlet pressure to 200 psig.

a. Connect pressure regulator to test set-up as

shown schematically in Figure 4-1.

Figure 4-1. Set-up for Testing Low Pressure Regulator