Question 77Refrigeration & AC - QMED

The correct answer is D) air and non-condensable gases in the condenser. An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, is typically caused by the presence of air and non-condensable gases in the condenser. These gases reduce the condenser's ability to effectively condense the refrigerant, leading to a rise in the system's head pressure. The other answer choices are incorrect because: A) water in the refrigerant would not cause a rise in head pressure without a change in cooling water temperature, B) a restriction in the liquid line would affect the low-pressure side, not the high-pressure side, and C) flooding back of liquid refrigerant would actually decrease the head pressure.