Maytag MFI2266AES Service Manual - Page 27

System Diagnosis CONDITION SUCTION PRESSURE VARIATION FROM NORMAL HEAD PRESSURE VARIATION FROM NORMAL T1 INLET TEMPERATURE VARIATION FROM NORMAL T2 OUTLET TEMPERATURE VARIATION FROM NORMAL T3 SUCTION TEMPERATURE VARIATION FROM NORMAL WATTAGE VARIATION FROM NORMAL Refrigerant Overcharge Increase Increase Warmer Warmer Colder Increase Shortage of Refrigerant Decrease Decrease or Increase See Text Colder Warmer Warmer Decrease Partial Restriction Decrease Decrease or Increase See Text Note 2 Colder Warmer Warmer Decrease Air in System Near Normal Increase Warmer Warmer Warmer Increase Low Ambient Installations (High Ambients the Reverse) Additional Heat Load Inefficient Compressor Decrease Increase Increase Decrease Increase Normal or Decrease Colder Warmer Warmer or Colder Warmer Warmer Warmer Warmer Decrease Warmer Warmer Increase Decrease Symptoms of an Overcharge • Above normal freezer temperatures. • Longer than normal or continuous run. • Freezing in refrigerator. • Higher than normal suction and head pressure. • Higher than normal wattage. • Evaporator inlet and outlet temperatures warmer than normal. • Suction tube temperature below ambient. Always check for separated heat exchanger when suction temperature is colder than ambient. Various conditons could indicate an overcharge. For example, if the cooling coil is not defrosted at regular intervals, due to a failure of the defrost system, the refrigerant will "flood out" and cause the suction line to frost or sweat. The cause of this problem should be corrected rather than to purge refrigerant from the sytem. Running the freezer section colder than necessary (-2 to -1 F. is considered normal package temperatures) or continuous running of the compressor for a variety of reasons, or the freezer fan motor not running, may give the indication of an overcharge. Symptoms of Refrigeration Shortage • Rise in food product temperature in both compartments. (See Note 1 below.) • Long or continuous run time. • Look for obvious traces of oil that would occur due to a leak or cracked refrigerant line. • Lower than normal wattage. • Compressor will be hot to touch because of the heat generated by the motor windings from long continuous running. It will not be as hot as it would be with a full charge and long run times for some other reason such as a dirty condenser. • Depending on the amount of the shortage, the condenser will not be hot, but closer to room temperature. The capillary tube will be warmer than normal from a slight shortage. • If the leak is on the high side of the system, both gauges will show lower than normal readings and will show progressively lower readings as this charge becomes less. The suction pressure guage will probably indicate a vacuum. • If the leak is on the low side of the system the suction pressure guage will be lower than normal - probably in a vacuum - and the head pressure gauge will be higher than normal. It will probably continue to become higher because air drawn in through the leak is compressed by the compressor and accumulates in ©2006 Maytag Services 16026312 27