l The magnetic valves that control the flow ofDETECTING AND CORRECTINGrefrigerantPROBLEMSl The wiring system that connects the sensingA number of symptoms indicate faulty operation ofelements to the solenoids of the magnetic valvesrefrigeration and air-conditioning plants. Figures 5-7,and the controller of the electric heaters5-8, and 5-9 list some of the problems along withTroubleHigh condensing pressure.Possible CauseCorrective MeasureAir on noncondensable gas in system.Purge air from condenserInlet water warm.Increase quantity of condensing water.Insufficient water flowing throughIncrease quantity of water.condenser.Condenser tubes clogged or scaled.Too much liquid in receiver,condenser tubes submerged in liquidrefrigerant.Clean condenser water tubes.Draw off liquid into service cylinder.Low condensing pressure.Too much water flowing throughcondenser.Reduce quantity of water.High suction pressure.Water too cold.Reduce quantity of water.Liquid refrigerant flooding back fromChange expansion valve adjustment,evaporator.examine fastening of thermal bulb.Leaky discharge valve.Remove head, examine valves.Replace any found defective.Overfeeding of expansion valve.Regulate expansion valve, check bulbattachment.Low suction pressure.Leaky suction valve.Restricted liquid line and expansionvalve or suction screens.Insufficient refrigerant in system.Too much oil circulating in system.Remove head, examine valve andreplace if worn.Rump down, remove, examine andclean screens,Check for refrigerant storage.Check for too much oil in circulation.Remove oil.Improper adjustment of expansionvalves.Adjust valve to give more flow.Expansion valve power element deadReplace expansion valve poweror weakelement.Figure 5-7.—Trouble diagnosis chart.5-13
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