TM 9-4120-357-14
(b) Remove screw, nut and washer from band clamp (10) which is secured to the casing, and remove and dis-
card drier-strainer.
CAUTION
When installing a new drier-strainer, make sure that the direction-
of-flow arrow is pointing down.
(c) Place band clamp (10) around new drier-strainer, and connect top and bottom flare nuts (9), finger tight.
(d) Secure band clamp to casing with a screw, washer and nut.
(c) Using two wrenches, one on drier-strainer connection and one on flare nut, tighten top and bottom flare
nuts.
(8) Connect a cylinder of dry nitrogen to the gage port of the suction line service valve, open both service valves
and the cylinder shutoff valve, and purge the refrigeration system for 3-5 minutes at (0.5 - 1 M3) CFM flow.
d. Test the system for leaks. Whenever a component of the refrigeration system has been replaced, the system
must be tested for refrigerant leak Three methods are available for detecting leaks: the electronic leak detector, the Hal-
ide torch, and the soap bubble method. The electronic leak detector method is preferred. Use GE type H10 electronic
leak detector or equivalent.
CAUTION
The electronic and the Halide torch leak detectors are sensitive to the
presence of refrigerant gas in the atmosphere. When refrigerant gas is
present in the atmosphere of the work area, false indications can result.
Use in a well ventilated but draft-free area.
(1) Electronic Leak Detector. Turn the electronic unit on, and slowly pass the probe around all points of the re-
frigeration system at which a leak could exist. Depending upon the type of detector used, a leak will be indicated by an
audible signal, a light, or by meter deflections.
(2) Halide Torch. Turn on the gas from the cylinder and light the torch. Adjust to obtain a stable light-blue flame.
Pass the open end of the sensing tube slowly around all locations at which a leak could exist. A small leak will be indi-
cated by the flame turning from blue to green. A large leak will be indicated by the flame turning from blue to indigo with
a red tip, or the torch may be extinguished.
(3) Soap Solution. Brush soap solution on all possible points of leakage, and watch for bubbles. Follow a defi-
nite sequence to avoid missing any points that should be tested. Wipe the solution from all joints, and mark any point at
which a leak is found.
e. Discharge the System. Whenever a leak is detected or a refrigeration component must be replaced, you must
discharge all gas from the refrigeration system. Discharge in accordance with paragraph 5-6.
f. Purging the System.
CAUTION
Whenever the refrigeration system has been opened to the atmos-
phere, you must install a new drier-strainer (dehydrator) before
purging and recharging the system.
With the refrigeration system discharged and a hose attached to the gage port of the suction service valve, connect a
cylinder of oil-pumped dry nitrogen to the gage port of the high-pressure service valve.
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