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Hi Mike, This is probably thermostatic expansion valve malfunction problem. The simple refrigeration process: is where a high pressure liquid refrigerant is forced thru a small orifice where the liquid quickly expands into a gas and at the same time drops pressure thus droping temperature, the refrigerating effect. All refrigerant has a temperature pressure relationship. As the temperature changes so does the pressure and visa versa. Example: R22 @ 100�= 196psig and at 50�=84psig or the sensible heat (total heat content) refrigerating effect equals 112� The expansion valve in this case, is a controlling variable orifice that I was talking about and throttles a given design amount of liquid refrigerant into evaporator. It uses a sensing blub on mounted the evaporator to modulate the varible orifice to control the amount of liquid refrigerant into the evaporator. Either the expansion valved has failed or has a loose sensing blub (not likely) as it's letting too much refrigerant into the evaporator at one time thus flooding the evaporator (A-coil) causing it too ice and at the same time starving the expansion valve inlet line where the line is getting flash over gas inside the line thus icing the outside of the line. This could also cause liquid refrigerant to be returned back to the compressor that could cause the compressor valves to break, hence my warning about adding refrigerant to a unkown problem. If the suction line on the compressor is frosting then liquid refrigerant is being returned to the compressor and your taking a gamble that the valves don't break. T_Bone
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