apply it to the suspected leaking joint with a soft brush.
1. Turn the balance knob clockwise. The red light
Wait for bubbles to appear under the clear, thick, soap
should be lit indicating the unit is on.
solution.
2. To balance the instrument, turn the balance
Find extremely small leaks by carefully examining
knob fully clockwise to maximum alarm. Turn knob
suspected places with a strong light. If necessary, use a
counterclockwise until alarm changes to fastest steady
mirror to view the rear side of joints or other
tick, the most sensitive position. Turning the bal-
connections suspected of leaking. Repair all leaks by
ance knob further counterclockwise will decrease
following the latest repair methods, and service the
sensitivity.
system after all pump down and system cleaning
3. When searching for a leak and a very small
guidelines are finished. Perform a full system check
amount of halogen gas enters the sensing tip, the ticking
before returning the unit back to the SE pool for issue.
signal will speed to a very low hum. As more gas enters
the tip, the low hum will change to a low siren. As the
Charging a System
concentration continues to build, the alarm signal will
continue to increase in frequency until a very high pitch
You will occasionally be required to top off the
siren is heard. The higher the alarm signal pitch, the
charge of refrigerant in an air-conditioner. This may be
heavier the concentration of halogen gas.
because of leaks or because you have had the system
open to work on it. If you have made major repairs, such
4. Due to the expanded dynamic range, large
as to the condenser or receiver, you may have
leaks can be detected even in areas of high
completely emptied the air-conditioner of refrigerant.
concentration without resetting the instrument's
In which case, you would have transferred the
balance control. After initial setup for maximum
refrigerant to one or more external cylinders for
sensitivity, and the unit has reached full siren, you can
storage. Whatever the circumstances, you must ensure
readjust to detect a larger leak by turning knob
the system is fully charged before it is used.
counterclockwise to a fast steady tick. Repeat as
necessary until the source is located. In windy areas, a
To replace partial amounts of refrigerant, you will
large leak can be extremely difficult to find because the
normally charge with gas, a procedure called low-side
escaping gas is rapidly carried away from the leak
charging. If you have to replace the entire charge of
source. Under these conditions, it may be necessary to
refrigerant, you'll charge with liquid, a procedure
shield the potential leak area.
called high-side charging.
5. In a situation where large leaks mask the
REFRIGERANT STORAGE CYLINDERS.--
presence of very small leaks, locate and repair large
Refrigerant can be drawn from the same storage
leaks first. Finding the small leaks will then become an
cylinder in either the gaseous or liquid state. A dual
easy task. When trying to locate a very "hard to find
port/dual access valve cylinder has two ports. You draw
leak," first isolate the potential leak area with a drop
gas from one port and liquid from the other. A single
cloth. Wait a few minutes and probe the shielded area.
port/single access valve cylinder has only one port. If
Continue this practice until all suspected areas have
refrigerant is drawn from an upright cylinder (valve at
been checked.
the top), it will be in the gaseous state. If the cylinder is
turned upside down (valve at the bottom), refrigerant is
6. In areas where background noise is a problem,
drawn in the liquid state.
you may want to use the earphone accessory available
for your leak detector. Remember that halogen gases
LOW-SIDE CHARGING.--In low-side charg-
are heavier than air. The first indication of the presence
ing, you charge the compressor with gas by using the
of halogen gases may be slightly below the actual leak
following procedures.
source. When searching for leaks, the sensing probe
1. Connect a hose between the center connection
should be moved at the rate of approximately 1 inch per
of the manifold test set and the cylinder of refrigerant
second.
(fig. 11-28). Tighten both connections. If using a single
SOAP AND WATER TEST.--Soap and water
port/single valve cylinder, ensure that the cylinder is in
may be used to test for leakage of any refrigerant having
the upright position (valve at the top).
pressure higher than atmospheric pressure. Make a
2. Connect a hose from the low-pressure side of
soap-and-water solution by mixing a considerable
the manifold test set to the suction side of the
amount of soap with water to a thick consistency. Let it
compressor. The service valve on the compressor
stand until the bubbles have disappeared, and then
11-29
