At what refrigerant charge should a system be serviced if it has been found leaking?

The correct answer is based on the importance of servicing a refrigerant system when it demonstrates a significant leakage rate. A 10% leakage rate indicates a serious problem that must be addressed to ensure the system operates efficiently and does not contribute to environmental pollution.

When a refrigerant system exhibits a 10% leakage rate, it is essential to service the system to identify and repair the leak. Regular maintenance and prompt action in such situations help prevent further loss of refrigerant, which can lead to inadequate cooling performance and increased operational costs. Additionally, refrigerants are subject to regulatory standards to minimize environmental impact, making it crucial to address any leaks promptly.

The other options do not reflect responsible practices in managing refrigerant systems. A threshold of less than 20% charge or being over the appropriate charge does not specifically address the need for servicing based on leakage rate. Meanwhile, waiting until a system reaches a 2% charge fails to prompt necessary action in a timely manner when a significant leak is already present.