Question 116Refrigeration & AC - QMED

The correct answer is C) higher than normal discharge pressure. When there is an excessive charge of refrigerant in a thermostatically controlled, air-cooled, refrigeration system using a thermostatic expansion valve (TXV), it can cause the discharge pressure to be higher than normal. This is because the excessive refrigerant charge leads to a higher pressure in the system, which the compressor must work against, resulting in a higher discharge pressure. The other options are incorrect because: A) oil foaming is caused by a low refrigerant charge, not an excessive charge; B) the compressor would not run continuously, as the high discharge pressure would eventually trip the high-pressure switch; and D) a higher than normal refrigerant charge would result in a lower than normal box temperature, not the other way around.