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TM 5-4128-257-15
the liquid sight glass have been eliminated, close the refrigerant control valve. Observe the liquid refrigerant sight indicator
for three to four minutes after flow clears to ascertain that sufficient refrigerant-12 has been added to the system.
CAUTION
Do not overcharge the refrigerant system. After each small quantity of refrigerant-12 has been added to
the refrigerant system, allow three to four minutes for the refrigerant to circulate before adding more
refrigerant. Do not attempt to meter the flow of refrigerant-12 with the air conditioner charge valve.
n.
Set master circuit breaker to OFF position,
o.
Note scale reading and add one additional pound of refrigerant-12 to refrigerant system.
p.
Remove the air conditioner right-side access panel assembly.
q.
Close air conditioner charge valve.
r.
Close the refrigerant-12 bottle valve.
s.
Disconnect the refrigerant supply hose from the refrigerant-12 bottle.
t.
Disconnect the evacuation and charge hose from the air conditioner charge valve and cap the charge valve.
WARINING
High pressure refrigerant is trapped in the charging line. Caution should be used in releasing this
pressure.
u.
Inspect the refrigerant system for leaks (para 7-6).
v.
Install the air conditioner right-side access panel assembly (para 3-29 c).
7-6.
Inspection Refrigerant System for Leaks
a.
An electronic type halogen leak detector is used to detect refrigerant system leaks. The leak detector is a very
sensitive device, and to some extent dangerous to use. It incorporates a sensing element that operates at approximately
1472F which is sufficiently hot to cause ignition. This device can be best utilized to detect small leaks because a large
area contaminated with leakage makes it difficult to pinpoint a leak.
(1) Leak test. Remove the access panel assemblies (para 3-23 a, 3-27 a and 3-29 a).
WARNING
Do not use this leak detector in the presence of explosive or flammable gases. The area in which the leak
detector is to be used must always be checked first with an explosimeter. If the atmosphere of the
compartment area causes any indication on the scale of the explosimeter, the compartment area must be
purged or cleared of all explosive vapor before the leak detector can be utilized.
CAUTION
Do not expose the leak detector probe to large leaks that can be detected without the use of the leak
detector. This will prevent damage to the leak detector probe.
(2) Pass the leak detector probe over all refrigerant lines, fittings, couplings, brazed joints and valves.
NOTE
To obtain good leak detection, avoid using the leak detector in a draft, also, avoid exposing the leak
detector probe to refrigerant leakage for a long period of time.
(3) Pass the leak detector probe over all accessible welded joints on components such as the condenser and
evaporator assemblies. Check the compressor housing and the refrigerant liquid sight indicator.
(4) Mark all leaks and repair them upon completion of leak test (para 7-14 and 7-15).
b.
A Halide torch leak detector can be utilized in much the same manner as the electronic type Halogen leak detector.
The same precautions concerning the utilization of the electronic type Halogen leak detector in the presence of explosive
or flammable gases is equally applicable to the utilization of the Halide torch.
(1) The Halide torch, when ignited gives off a greenish flame in the presence of a small refrigerant leak. It will give
off a dense blue flame with a reddish tip or it may be extinguished in the presence of a large leak.
(2) The Halide torch is extremely sensitive. The presence of refrigerant-12 in the air due to changing refrigerant
bottles or making repairs may interfere with a test by coloring the flame regardless of the position of the searching tube. In
this case, it will be necessary to ventilate the compartment thoroughly.
7-3
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