RS5290000 Rev. 0 46 April 1998
Dehydrating Sealed Refrigeration System
Moisture in a refrigerator sealed system exposed to
heat generated by the compressor and motor reacts
chemically with refrigerant and oil in the system and
forms corrosive hydrochloric and hydrofluoric acids.
These acids contribute to the breakdown of motor
winding insulation and corrosion of compressor
working parts, causing compressor failure.
In addition, sludge, a residue of the chemical reaction,
coats all surfaces of sealed system, and will eventually
restrict refrigerant flow through capillary tube.
To dehydrate sealed system, evacuate system (see
paragraph Evacuation).
Leak Testing
DANGER
To prevent serious injury or death from violent
explosions, NEVER use oxygen or acetylene for
pressure testing or clean out of refrigeration systems.
Free oxygen will explode on contact with oil. Acetylene
will explode spontaneously when put under pressure.
It is important to check sealed system for refrigerant
leaks. Undetected leaks can lead to repeated service
calls and eventually result in system contamination,
restrictions, and premature compressor failure.
Refrigerant leaks are best detected with halide or
electronic leak detectors.
Testing Systems Containing a Refrigerant Charge
1. Stop the operation (turn refrigerator off).
2. Holding leak detector exploring tube as close to
system tubing as possible, check all piping, joints,
and fittings.
NOTE: Use soap suds on areas leak detector cannot
reach or reliably test.
Testing Systems Containing No Refrigerant Charge
1. Connect cylinder of nitrogen, through gauge
manifold, to process tube of compressor and liquid
line strainer.
2. Open valves on nitrogen cylinder and gage
manifold. Allow pressure to build within sealed
system.
3. Check for leaks using soap suds.
If a leak is detected in a joint, do not to attempt to repair
by applying additional brazing material. Joint must be
disassembled, cleaned and rebrazed. Capture refrigerant
charge (if system is charged), unbraze joint, clean all
parts, then rebraze.
If leak is detected in tubing, replace tubing. If leak is
detected in either coil, replace faulty coil.
Service Procedures
WARNING
To avoid risk of electrical shock, personal injury, or death, disconnect electrical power source to unit and discharge
capacitor through a resistor before attempting to service, unless test procedures require power to be connected.
Ensure all earth wires are connected before certifying unit as repaired and/or operational.
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