A new split system should be checked for leaks by?

Pressurizing the system with a few ounces of system refrigerant and an inert gas is the correct approach to checking for leaks in a new split system. This method is beneficial because it allows for the detection of any potential leaks in the refrigeration system without introducing substances that could harm the environment or alter the operating characteristics of the system. Using the system refrigerant ensures that the pressure tests are representative of the actual conditions under which the system will operate.

Additionally, incorporating an inert gas, like nitrogen, provides a safe means to pressurize the system without the risk of damaging sensitive components or affecting the properties of the refrigerant being used.

While other options suggest using various refrigerants or combinations that are not suitable for leak testing, they can pose environmental risks, particularly with substances like HCFC-22 or CFC-12, which are regulated and being phased out due to their ozone-depleting potential. Therefore, the combination of system refrigerant, when used correctly alongside an inert gas, ensures both safety and efficacy in leak detection.