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 TM 55-1905-220-14-8
4-29. AIR CONDITIONING SYSTEM - MAINTENANCE INSTRUCTIONS (Continued).
(c) If the system is losing refrigerant, and a piping leak cannot be detected, the condenser should
be tested for leaks.
(d) Before testing for leaks, at times it may be necessary to raise the pressure in the system by
reducing the flow of condenser water. Proceed to test for leaks as follows:
1 Using electronic leak detector.
First, adjust the sensitivity of the electronic leak detector according to the instructions of
the manufacturer. Next, move detector probe tip around the joint or suspected leak area
at about 1 or 2 inches (2.54 to 5.08 cm) per second. The probe continuously draws in air.
As the probe tip passes near a leak, leaking refrigerant gas is drawn in and detected. A
light in the transparent probe gives a short flash for a small leak and a long flash for a
large leak.
2 Using halide leak detector.
The halide leak detector consist of a burner, needle valve, suction (exploring) tube and a
chimney with a copper reaction plate. Some torches use alcohol and others propane as fuel.
First, adjust the detector flame so that top of blue flame cone is level with or slightly above
reaction plate. Next, place end of exploring tube at point to be tested. The exploring tube
draws in a sample of air to the burner where the refrigerant decomposes by reaction with the
copper plate and changes the flame color. Observe the flame. Small leaks give a greenish
tint and larger ones a vivid blue.
(3) Testing for Condenser Leaks.
(a) To avoid serious loss of refrigerant or possible entrance of sea water into the refrigerant
system, test the condenser for leaks periodically, preferably every two weeks. Also test the
condenser for leaks whenever the system is losing refrigerant and a piping leak cannot be
found.
(b) If possible, test the condenser after it has been shut down for twelve hours. At the end of this
time, usually there is a small air pocket at the top of the water heads. To test, slowly open
the water head vent valves' one at a time, and insert the exploring probe or tube of the leak
detector. If this test indicates the presence of refrigerant-12, test the tube sheets and
individual tubes for leaks after draining water and removing water heads.
4-901
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