Section III. TROUBLESHOOTING - TM-9-6685-202-140046

TM 9-6685-202-14

(1) Fill pump with Cenco No. 93050 vacuum

(3) Release the cistern pressure.

pump lubricating oil, Federal stock number 9150-273-

(4) Remove the vacuum pump.

8663, to sight level line as indicated in window on one

e. Removing Moisture from the Barometer Tube. If

side of pump. On the 4310-203-3057 vacuum pump

the procedures of paragraph 3-5 are followed closely, it

remove the top cover for filling. The 4931-929-8403 is

is improbable that there will be any moisture in the tube.

filled by pouring oil through the exhaust port.

However, it is possible for moisture to collect in the

(2) Frequency of oil change depends on

cistern due to condensation if the cistern is left open to

service or use of pump. In a vaporless and dustless

atmospheric pressure. Under certain circumstances

system, change oil only once every 6 months.

some of this moisture may be transferred to the tube by

(3) When oil has been contaminated, drain

the mercury. Moisture in the tube will form water vapor

from the pump. Flush pump with oil (Cenco No. 93050,

above the mercury which will depress the column in the

or equal) and refill with vacuum pump lubricating oil,

same manner as an air bubble. However, it cannot be

Cenco No. 93050, Federal stock number 9150-273-

removed in the same manner as an air bubble because

8663.

as pressure is applied to force the vapor past the tube

seal valve it will merely condense and revaporize as the

(4) Most of the oil can be drained through the

pressure is released. In removing moisture, follow the

drain cock. To completely remove all oil, remove cover,

same general procedure as in preparing the barometer

invert pump, and turn shaft through several revolutions.

for use after shipment or storage. Refer to paragraph 3-

4-7. Operator Maintenance of Constant Vacuum

Regulator 6685-306-5604

f. Replacing the Light Bulb. Unscrew the light bulb

Operator responsibility for the maintenance of

from its bracket. Replace with GE Type 323, 3 volts,

the vacuum regulator is confined to visual inspection

0.19 amperes, instrument light bulb, Federal stock

and operation of the regulator.

number 6240-155-7864.

4-8. Recording Repairs

Repairs will be made in accordance with

g. Replacing the Batteries. The batteries can be

procedures and standards prescribed in appropriate

replaced, using the method described in paragraph 3-4.

technical manuals.

The equipment record system

Batteries should be replaced at regular intervals before

provides for recording required repairs accomplished on

they can become overaged and swell in the tube. They

specific items of equipment. This will include, but is not

should be removed if the instrument is not to be used for

limited to, adjusting, cleaning, and replacement.

a considerable period.

Deficiencies discovered before, during, and after

4-6. Operator's Maintenance of Vacuum Pump 3410-

operation that cannot be corrected by the operator will

203-3057 or 4931-929-8403

be reported on DA Form 2404.

Deficiencies

a. General. Operator maintenance of the vacuum

immediately corrected by the operator are not recorded,

pump is confined to visual inspection and changing of

except when such corrections are made by replacing

the oil used in the pump.

parts which constitute repairs above the operator

b. Maintaining Oil Level. Maintain the oil level in

maintenance level. Such repairs will be recorded as

the pump as follows:

organizational maintenance.

Section III. TROUBLESHOOTING

means of symptoms and tests. The tests and remedies

4-9. Purpose and Scope

provided herein are governed by the scope of the level

Troubleshooting is a systematic isolation and

of maintenance of the barometer.

remedy of malfunctions and defective components by

4-8