Which of the following is not a symptom of a hermetic system that is low on refrigerant?

A hermetic system that is low on refrigerant typically exhibits various symptoms indicating that the system is not operating efficiently. High head pressure is not usually associated with low refrigerant levels; in fact, low refrigerant tends to result in lower head pressure, as there is insufficient refrigerant to absorb and dissipate heat effectively in the condenser.

On the other hand, frost on the suction line is a common symptom of low refrigerant. With inadequate refrigerant, the evaporator coil can become too cold, leading to moisture freezing on the line. Similarly, low ambient temperatures can also cause low refrigerant conditions to manifest as lower than normal head pressures. Increased energy consumption is often seen in systems struggling to maintain efficiency that are low on refrigerant due to the compressor working harder to achieve the desired cooling effect.

Thus, a high head pressure would not typically be expected in a hermetic system that is low on refrigerant, making it the correct response to the question.