Chapter 3 HVAC Tools, Equipment, and Service Information 45
A soap solution can be made by mixing a small
amount of dishwashing liquid or other soap with water.
The solution is then sprayed or poured on the suspected
leak area. Leaking refrigerant will form bubbles. The size of
the bubbles and how rapidly they form will increase with
the size of the leak. Slight foaming will occur at the site
of a small leak, while large bubbles will be seen at a seri-
ous leak. If large bubbles form at a rate faster than one per
second, the leak can be considered severe.
Refrigerant Identifi ers
To avoid contaminating the recycling equipment with
incorrect or contaminated refrigerant, many air condition-
ing specialists identify the refrigerant before beginning
service. A refrigerant identifi er, Figure 3-11, is used to
determine what kind of refrigerant is installed in a refrig-
eration system or storage container. Refrigerant identifi -
ers are usually designed to tell whether the refrigerant is
R-134a, R-12, or an unknown blend. Some refrigerant
identifi ers can also determine the percentage of each type
of refrigerant, and identify contaminated refrigerant.
Disposing of Contaminated Refrigerant
When contaminated or unfamiliar refrigerant has been
found, it must be stored in special containers pending its
disposal. Contaminated refrigerant containers are gray with
a yellow top. Contaminated refrigerant containers should
be shipped to a reclaiming facility for recycling or disposal.
Storage and recycling of contaminated and unfamiliar
refrigerant was discussed in Chapter 2. More information
on refrigerants is located in Chapter 6.
Electrical Test Equipment
The HVAC system contains many electrical compo-
nents, wire harnesses, and electrical connectors that require
testing. The technician will frequently have to diagnose
electrical devices and wiring.
Note: Electrical values such as voltage and
resistance will be explained in more detail
in Chapter 4.
Test Lights
The test light is often used to check whether electric-
ity is reaching a particular point in an electrical circuit, or
to detect a circuit not allowing current to fl ow. The non-
powered test light, Figure 3-12, can be used to probe
electrical circuits to determine whether voltage is present.
A powered test light resembles the non-powered light but
has an internal battery. The battery supplies an electrical
power source to determine whether a circuit is complete.
Test lights can be useful when working on various parts of
the HVAC electrical system, but must be used with care
when working on any electronic system. The test light has
the potential to severely damage electronic circuits. Avoid
using test lights unless specifi cally instructed by the HVAC
system manufacturers’ service literature.
Multimeters
Multimeters, such as the one in Figure 3-13, are
devices for reading electrical values. Modern multimeters
can read all common electrical values (voltage, resistance,
and amperage). Many modern multimeters are able to read
voltage waveforms and provide other information. Modern
multimeters are digital types that display the electrical
reading as a number. Analog multimeters use a needle,
which moves against a calibrated background. Modern
multimeters contain the individual meters discussed in the
following paragraphs.
Note: Only digital multimeters should be
used for air conditioning and other
automotive work. Make sure any meter or
test light has a minimum of 10 meg ohm impedance.
Figure 3-11. A refrigerant identifi er should always be used
before recovering refrigerant.
Figure 3-12. Non-powered test lights are useful for determining
if voltage is present in a circuit.