21
5. Using an acid test kit (one shot or conven tional kit), test
the oil for acid content ac cord ing to the in struc tions
with the kit.
6. If any evidence of a burnout is found, no matter how
slight, the system will need to be cleaned up following
proper pro ce dures.
7. Install the replacement compressor.
8. Pressurize with a combination of R-22 and nitrogen
and leak test all con nec tions with an elec tron ic or
Halide leak de tec tor. Recover re frig er ant and re pair
any leaks found.
Repeat Step 8 to insure no more leaks are present.
9. Evacuate the system with a good vac u um pump
capable of a fi nal vac u um of 300 microns or less.
The system should be evac u at ed through both liq uid
line and suc tion line gauge ports. While the unit is
being evac u at ed, seal all openings on the defective
com pres sor. Compressor man u fac tur ers will void
warranties on units received not properly sealed. Do
not distort the man u fac tur ers tube con nec tions.
10. Recharge the system with the correct amount of
refrigerant. The proper re frig er ant charge will be
found on the unit rating plate. The use of an accurate
measuring device, such as a charging cylinder,
elec tron ic scales or similar de vice is necessary.
CAPACITORS
Many motor capacitors are internally fused. Shorting the
terminals will blow the fuse, ruin ing the capacitor. A 20,000
ohm 2 watt resistor can be used to discharge ca pac i tors
safe ly. Remove wires from ca pac i tor and place resistor
across terminals. When checking a dual ca pac i tor with
a ca pac i tor analyzer or ohmmeter, both sides must be
tested.
Capacitor Check with Ca pac i tor Analyzer
The capacitor analyzer will show whether the capacitor is
"open" or "shorted." It will tell wheth er the capacitor is within
its mi cro far ads rating and it will show whether the capacitor
is operating at the proper power-factor per cent age. The
instrument will automatically dis charge the capacitor when
the test switch is re leased
Capacitor Connections
The starting winding of a motor can be dam aged by a
shorted and grounded run ning ca pac i tor. This damage
usually can be avoided by prop er con nec tion of the run ning
ca pac i tor terminals.
From the supply line on a typical 230 volt circuit, a 115 volt
potential exists from the "R" terminal to ground through a
possible short in the capacitor. However, from the "S" or
start terminal, a much high er potential, possibly as high as
400 volts, ex ists because of the counter EMF generated
in the start winding. Therefore, the pos si bil i ty of capacitor
fail ure is much greater when the identifi ed terminal is con-
nect ed to the “S" or start terminal. The iden ti fi ed terminal
should always be connected to the supply line, or "R"
terminal, never to the "S" terminal.
When connected properly, a shorted or grounded run-
ning-capacitor will result in a direct short to ground from
the "R" ter mi nal and will blow the line fuse. The motor
pro tec tor will protect the main winding from excessive
tem perature.
Hazard of shock and elec tro cu tion. A ca pac i tor can
hold a charge for long pe ri ods of time. A service
tech ni cian who touches these ter mi nals can be
in jured. Never dis charge the ca pac i tor by shorting
across the ter mi nals with a screwdriver.
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