SERVICING
39
S-101 LEAK TESTING
Refrigerant leaks are best detected with a halide or electronic
leak detector.
However, on outdoor installed systems, provisions must be
made to shield the copper element of an halide torch from the
sun and wind conditions in order to be able to see the element
properly.
NOTE:
The flame of the halide detector will glow green in the
presence of R-22 refrigerant.
For a system that contains a refrigerant charge and is sus-
pected of having a leak, stop the operation and hold the explor-
ing tube of the detector as close to the tube as possible, check
all piping and fittings. If a leak is detected, do not attempt to
apply more brazing to the joint. Remove and capture the charge,
unbraze the joint, clean and rebraze.
For a system that has been newly repaired and does not con-
tain a charge, connect a cylinder of refrigerant, through a gauge
manifold, to the liquid and suction line dill valves and/or liquid
line dill valve and compressor process tube.
NOTE:
Refrigerant hoses must be equipped with dill valve de-
pressors or a special adaptor used. Open the valve on the
cylinder and manifold and allow the pressure to build up within
the system. Check for and handle leaks, as described above.
After the test has been completed, remove and capture the
leak test refrigerant.
S-102 EVACUATION
This is the most important part of the entire service procedure.
The life and efficiency of the equipment is dependent upon the
thoroughness exercised by the serviceman when evacuating
air (non-condensable) and moisture from the system.
Air in a system causes high condensing temperature and pres-
sure, resulting in increased power input and reduced perfor-
mance.
Moisture chemically reacts with the refrigerant and oil to form
corrosive hydrofluoric and hydrochloric acids. These attack
motor windings and parts, causing breakdown.
The equipment required to thoroughly evacuate the system is
a high vacuum pump, capable of producing a vacuum equiva-
lent to 25 microns absolute and a thermocouple vacuum gauge
to give a true reading of the vacuum in the system
NOTE:
Never use the system compressor as a vacuum pump
or run when under a high vacuum. Motor damage could occur.
SCROLL COMPRESSORS
Do not front seat the service valve(s) with the
compressor operating in an attempt to save
refrigerant. With the suction line of the compressor
closed or severely restricted, the scroll compressor
will draw a deep vacuum very quickly. This vacuum
can cause internal arcing of the fusite, resulting in a
damaged or failed compressor.
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S
U
P
E
RHE
AT
@ O
.D
. UN
IT
OUTDOOR TEMPERATURE
DESIRED SUPERHEAT vs OUTDOOR TEMPERATURE
90°
F I
nd
oo
r
70
° F
In
d
o
or
75
° F
In
do
or
80
° F
In
do
or
85
° F
In
do
or