Maytag MFI2266AES Service Manual - Page 12

Service Procedures ! WARNING To avoid risk of electrical shock, personal injury, or death, disconnect electrical power source to unit, unless test procedures require power to be connected. Discharge capacitor through a 10,000 ohm resistor before attempting to service. Ensure all ground wires are connected before certifying unit as repaired and/or operational. 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 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 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 gauge 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. ! DANGER To avoid risk of serious injury or death from violent explosions, NEVER use oxygen or acetylene for pressure testing or cleaning 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 unit 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. 12 16026312 ©2006 Maytag Services