Valves

TM 5-4130-234-13&P

(1) Uncap unions (17, 18, fig. 2-3) and connect

minutes and observe indication on gage (26). Indication

certified gages covering the ranges of gages (9, 10) into a

must be less than 100 microns.

pressure line between unions (17, 18) and a pressure

(4) If gage (26) indicates more than 100 microns,

regulator. Calibrate in 20 psig intervals to 60 psig for gage

vacuum system leakage is excessive. Locate leakage with

(10), and 140 psig for gage (9).

leak detector in accordance with Chapter 2, paragraph 2-4.

(2) Gages (9, 10) must indicate within two percent

If required, replace defective parts.

of their respective certified gages.

b. If gages are defective, replace as follows:

5-11. Valves (44, fig. 5-2)

(1) Remove attaching parts (74 thru 79, fig. 5-2).

a. Remove valves (44) as follows:

(2) Hold elbow (73) with gage and loosen nut (72) .

(1) Unplug to separate thermistor (part of item 14)

(3) Remove elbow (73) from defective gage.

and set thermistor half with wiring aside.

(4) Tape lubricate threads of new gage before

(2) Apply heat to solder joints of valves (44) to be

threading elbow (73) in place.

separated, and separate parts (21 thru 24) with thermistor

(5) Thread nut (72) into elbow (73) and install

half from valves (44) before solder joints can cool.

attaching parts (74 thru 79).

(3) Remove nuts (40), washers (41, 42), and

screws (43).

5-14. Beaker (84, fig. 5-2)

(4) Apply heat to remaining solder joint of valve to

a. If beaker is defective, apply heat to solder joints of

be separated, and separate valve from elbow (23) or tubing

valves (89) and separate beaker (84) with elbows (83) and

(26) before solder joint can cool.

tubing (71) from valves (89) before solder joint can cool.

b. Replace valves (44) in reverse of removal order.

b. Unthread elbows (83) with tubing (71) from beaker

Tin solder joints with solder. Secure valves with attaching

(84).

parts and plug-in thermistor halves.

c. Clean threads of elbows (83) and tape lubricate

threads before threading elbows (83) with tubing (71) on

5-12. Vacuum Pump (57, fig. 5-2)

new beaker (84).

a. Verify vacuum pump for defects as follows:

d. Tin tubing (71) and valves (89) together, using

(1) Connect hose assembly (8) with gaskets (2, 3)

solder.

between union (25, fig. 2-3) and valve (5). Cap union (24).

(2) Open valves (2, 5) and close valves (12, 14).

(3) Set circuit breaker (22) to ON and switch (21)

5-15. Valves (89, fig. 5-2)

to VAC ON. Open valve (1) slowly.

a. If valves are defective, remove attaching parts (85

(4) Operate vacuum pump for 1 hour. Operation

thru 88).

must be at an ambient temperature of 80 to 110 OF (26.7

b. Apply heat to solder joint of valves and separate

to 43.3 ). Open valve (5) to break vacuum to allow

valves from tubings (71) before solder joint can cool.

pressure to return to atmospheric pressure.

Before

c. Tin tubings (71) and new valves (89) together, u

breaking vacuum, record indication on gage (26), the

sin g solder.

ambient temperature, terminal voltage and amperage at

d. Install attaching parts (85 thru 88) to secure valves.

vacuum pump motor.

(5) If gage (26) records greater than 100 microns

5-16. Pressure Switch (96, fig. 5-2)

after one hour of evacuation, vacuum pump motor

a. Verify pressure switch for defects before replacing.

amperage is greater than given on nameplate, or the

Perform test as follows:

vacuum system does not operate continuously for one

(1) Connect a 120-volt light bulb between terminals 4

hour. Replace vacuum pump in accordance with Section

and 6 of terminal strip (167). (See fig. 5-1 for wiring

IV. If minor repair of the vacuum pump is required, refer to

diagram.)

Chapter 6.

(2) Set circuit breaker (22, fig. 2-3) to ON and switch

(6) Close valve (2), set switch (21) to OFF, and

/21) to HEATER ON, light bulb must light.

disconnect hose assembly.

(3) Allow tank heater to cycle on and off while

observing gage (7). Light bulb must not light when gage

5-13.

Gages (80, 81, fig. 5-2)

(7) indicates 69 5 psig and must light when gage (7)

indicates 58 5 psig. Light bulb must go out when gage

a. Verify gages for defects before replacement as

(7) indication exceeds 69 5 psig.

follows:

5-9