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 TM 55-1905-219-14-8
4-28. 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, perferably 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.
4-871
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