What is an indicator of a leak in a high-pressure system?

Excessive superheat is a significant indicator of a leak in a high-pressure system. Superheat measures the temperature of a vapor above its boiling point at a given pressure, and when there is a leak, the refrigerant charge can diminish. This reduction in refrigerant affects the system's ability to absorb heat effectively, leading to increased superheat as the vapor temperature rises without adequate liquid refrigerant to maintain proper heat exchange.

In contrast, high head pressure typically indicates a system that is overcharged or experiencing a restriction, rather than a leak. Low water temperature is not directly relevant as an indicator of leaks in refrigerant systems since it pertains more to the cooling effect rather than refrigerant integrity. Frequent purging might be a response to various issues, such as air or moisture in the system, but does not specifically indicate a refrigerant leak like excessive superheat does.