Testing for Leaks.

TM 5-4110-217-14

a. Change Dehydrator.

If activated silicagel

c. Use steel wool and clean Inside of socket and

outside of tube for a length greater than the depth of the

charge of dehydrator has absorbed all the moisture it can

socket. Clean to a bright finish; remove all foreign

hold, change the dehydrator (para 6-17). Run on this for

substances such as oil, scale, and oxides. Do not

approximately one day, then change again to another

handle clean surfaces.

fresh dehydrator. This may strip enough moisture from

d. When brazing at valve socket, partly open

system to correct the condition.

b. Use Service Dehydrator. Operate the unit

valve to avoid damaging valve seat or seat disk by

thermal expansion.

approximately an hour with service drier and replace

e. Apply flux evenly to outside of socket end and

dehydrator on unit with a fresh dehydrator.

the tube to distance close to the scribe line.

f. Apply only enough heat to cause the solder to

6-9. Testing for Leaks.

flow Apply heat to socket uniformly in order to draw the

solder into the joint. Continue heating until the flux

To test for leaks, use Halide leak detector.

becomes liquid or has the appearance of water. In

a. Follow instructions provided with Halide leak

soldering at sockets of valves, direct flame away from

detector Use only kind of fuel recommended by

body and towards tube so that excess heat is not

instruction sheet supplied with unit.

absorbed by internal parts of valve.

b. Hold open end of leak detector finder tube near

g. Lay solder firmly against junction of socket and

each soldered joint and fitting. If burned flame turns

tubing and permit the alloy to flow throughout the joint.

blue-green, a leak is indicated. If a leak is indicated,

h. When solder becomes set, apply wet cloth or

close nearest valves on each side of leak; release

swab to the joint to carry away excess heat and to

pressure, and make repair before operating refrigeration

remove residual flux. If necessary, use a wire brush to

unit.

remove all flux.

6-10.

Soldering.

6-11.

Use of Wrenches on Flared Fittings.

Many sections of tubing in the refrigeration system

are connected by means of hard soldered joints.

The following precautions are advised in regard to

Although established soldering principles are used, the

flare nuts used in conjunction with copper tubing.

following precautions should be observed:

a. Overtightening of Flare Nuts. As copper tub-

Cut tubing square and remove all burrs.

ing is relatively soft, overtightening of flare nuts will ruin

When tubing is mated to the socket of a fitting,

the copper flare.

make a light scribe line or other equivalent marking on

b. Hardening of Flares. Continued tightening of

tubing at a distance of 1-inch plus depth of the socket

flare nuts will in time cause a hardening effect of the

from the tube end. This provides an accurate method for

copper flare. To soften tubing which has become hard,

checking that tubing is fully engaged in the socket

apply torch to the hardened section until dull red; then

throughout soldering operation.

quench in water.

6-3