Rheem RARL-JEC Installation Instructions - Page 44

THERMOSTATIC EXPANSION VALVES SYMPTOMS POSSIBLE CAUSE High Superheat, Low Suction Pressure Moisture freezing and blocking valve Dirt or foreign material blocking valve Low refrigerant charge Vapor bubbles in liquid line Valve feeds too much refrigerant, with low superheat and higher than mal suction pressure Misapplication of internally equalized valve Plugged external equalizer line Undersized TEV Loss of charge from power head sensing bulb Charge migration from sensing bulb to power head (Warm power head with warm, wet cloth. Does valve operate correctly now?) Improper superheat adjustment (Only applicable to TEV with adjustable superheat settings) Moisture causing valve to stick open. Dirt or foreign material causing valve to stick open TEV seat leak (A gurgling or hissing sound is heard AT THE TEV during the off cycle, if this is the cause.) NOT APPLICABLE TO BLEED PORT VALVES. Oversized TEV Incorrect sensing bulb location Compressor flood back upon start up Low superheat adjustment (only applicable to TEV with adjustable superheat setting) Incorrectly installed, or restricted external equalizer line Refrigerant drainage from flooded evaporator Compressor in cold location Any of the causes listed under Symptoms of Problem #2 CHECK OR REMEDIES Recover charge, install filter-drier, evacuate system, recharge Recover charge, install filter-drier, evacuate system, recharge Correct the charge Remove restriction in liquid line Correct the refrigerant charge Remove non-condensible gases Size liquid line correctly Use correct TEV Remove external equalizer line restriction Replace with correct valve Replace power head or complete TEV Ensure TEV is warmer than sensing bulb Adjust superheat setting counterclockwise Recover refrigerant, replace filterdrier, evacuate system and then norrecharge Recover refrigerant, replace filterdrier, evacuate system and recharge Replace the TEV Install correct TEV Install bulb with two mounting straps, in 2:00 or 4:00 position on suction line, with insulation Turn superheat adjustment clockwise Remove restriction, or relocate external equalizer Install trap riser to the top of the evaporator coil Install crankcase heater on compressor Any of the solutions listed under Solutions of Problem #2 44