WD Catalog 2018

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6-9 - -
Electronic detectors have a probe that is moved around the AC
system. Where refrigerant is present, a change in current flow inside
the probe is sensed by an electrical circuit. This activates a buzzer
which signals the user about the presence of a refrigerant leak.
Figure 6-8 shows an electronic leak detector of the negative corona
type.
8. Flushing Kit
A flushing kit is used to remove contaminants from AC system hoses,
evaporator and condenser. Any other components should be bench
checked or replaced as flushing is either not effective or will cause dam-
age. Flushing these components is recommended when you replace the
compressor or find contamination in other system components (receiver-
drier, expansion valve, or at connections). Flushing must be done with a
"closed-loop" flushing kit using the Recovery/Recycle station.
9. Heater System Service Tools
In addition to normal tool box items, several test devices are required for
effective cooling system service. These are a pressure tester, hydrometer
and thermostat tester. The pressure tester is a simple hand pump with
a pressure gauge, hose, and adapters. The adapters are used to connect
the tester to the radiator filler neck or to the pressure cap. You use the
pump to apply pressure to the cooling system or cap. Then you check for
system leaks or for cap function.
A special cooling system hydrometer is used to draw coolant from
the radiator into a clear tube containing a float. The float has a scale you
read and relate to a scale on the hydrometer. The hydrometer scale
corresponds to a temperature level at which the coolant will freeze.
Air Conditioning System Service Tools
Figure 6-8
The electronic leak detector
is a small hand held device
that is easy to use. It de-
tects R-12 and R-134a leaks
as small as one half ounce
per year.
Figure 6-9
Flushing kit to use with one
brand of recycling station
(Sercon).