Many compressor failures are caused by the following
conditions:
1. Improper air flow over the evaporator.
2. Overcharged refrigerant system causing liquid to be
returned to the compressor.
3. Restricted refrigerant system.
4. Lack of lubrication.
5. Liquid refrigerant returning to compressor causing oil
to be washed out of bearings.
6. Noncondensables such as air and moisture in
the system. Moisture is extremely destructive to a
refrigerant system.
Single Phase Resistance Test
Remove the leads from the compressor terminals and set
the ohmmeter on the lowest scale (R x 1).
Touch the leads of the ohmmeter from terminals common
to start (“C” to “S”). Next, touch the leads of the ohmmeter
from terminals common to run (“C” to “R”).
Add values “C” to “S” and “C” to “R” together and
check resistance from start to run terminals (“S” to “R”).
Resistance “S” to “R” should equal the total of “C” to “S”
and “C” to “R.”
In a single phase PSC compressor motor, the highest
value will be from the start to the run connections (“S” to
“R”). The next highest resistance is from the start to the
common connections (“S” to “C”). The lowest resistance
is from the run to common. (“C” to “R”) Before replacing a
compressor, check to be sure it is defective.
Check the complete electrical system to the compressor
and compressor internal electrical system, check to be
certain that compressor is not out on internal overload.
Complete evaluation of the system must be made
when ever you suspect the compressor is defective.
If the compressor has been operating for sometime, a
careful
examination must be made to determine why the
compressor failed.
19
Recommended procedure for compressor
replacement
1. Be certain to perform all necessary electrical and
refrigeration tests to be sure the compressor is
actually defective before replacing.
2. Recover all refrigerant from the system though
the process tubes.
PROPER HANDLING OF
RECOVERED REFRIGERANT ACCORDING TO
EPA REGULATIONS IS REQUIRED.
Do not use
gauge manifold for this purpose if there has been
a burnout. You will contaminate your manifold and
hoses. Use a Schrader valve adapter and copper
tubing for burnout failures.
Unplug and/or disconnect all electrical power
to the unit before performing inspections,
maintenances or service.
Failure to do so could result in electric shock,
serious injury or death.
WARNING
RISK OF ELECTRIC SHOCK
Sealed Refrigeration System contains refrigerant
and oil under high pressure.
Proper safety procedures must be followed,
and proper protective clothing must be worn
when working with refrigerants.
Failure to follow these procedures could
result in serious injury or death.
WARNING
HIGH PRESSURE HAZARD
Extreme care, proper judgment and all safety
procedures must be followed when testing,
troubleshooting, handling or working around
unit while in operation with high temperature
components. Wear protective safety aids
such as: gloves, clothing etc.
Failure to do so could result in serious burn
injury.
WARNING
HIGH TEMPERATURES
The use of a torch requires extreme care and proper
judgment. Follow all safety recommended precautions
and protect surrounding areas with fire proof materials.
Have a fire extinguisher readily available. Failure to follow
this notice could result in moderate to serious property
damage.
NOTICE
FIRE HAZARD
COMPReSSOR RePLACeMeNT
