Final answer:
The most efficient method of leak checking a charged low-pressure system is to use a manometer. A manometer measures pressure by comparing it to the pressure exerted by a fluid column. When using a manometer for leak checking, any pressure difference between the system being tested and the reference fluid can be observed.
Step-by-step explanation:
The most efficient method of leak checking a charged low-pressure system is to use a manometer. A manometer is a device that measures pressure by comparing it to the pressure exerted by a fluid column. It works by balancing the pressure of the system being tested with the pressure of a reference column of fluid.
When using a manometer for leak checking, the system being tested is connected to the manometer, and any pressure difference between the system and the reference fluid can be observed. If there is a leak, the pressure in the system will change, causing a detectable difference in the manometer reading. This allows the leak to be identified and repaired.
For example, if the system being checked has a pressure of 10 psi and the reference fluid in the manometer has a pressure of 5 psi, a leak in the system would cause the manometer to show a different pressure, indicating the presence of a leak.