ESCO Air Conditioning Practice Exam

In this scenario, the most likely cause of the issue described is a restriction of the return air or a dirty evaporator. When the air conditioning system is running constantly but not cooling effectively, and the suction line is very cold while the compressor is sweating, it indicates that the system is not receiving enough warm air to properly cool. This lack of warm air can be due to a restriction in the return air ducts or a dirty evaporator coil, hindering the heat exchange process. Option B (An overcharged system) is not the correct answer because an overcharged system would typically result in high pressures and temperatures, leading to other symptoms like increased power consumption, higher head pressure, and possible compressor damage. Option C (A malfunctioning thermostat) is an unlikely cause in this scenario because a malfunctioning thermostat would not directly result in the system running constantly but not cooling sufficiently. Option D (Insufficient refrigerant) could also cause cooling issues; however, the symptoms described in the question, such as a very cold suction line and a sweating compressor, are more indicative of a restriction of the return air or a dirty evaporator coil.