How should leak-testing be performed after installation?

• A. Rely on visual inspection without testing.
• B. Use hot water for pressure test.
• C. Apply a simple soap-bubble test only.
• D. Perform a pressure test with an inert gas, verify for leaks with appropriate detection methods, and document the results.

Answer: (D)

Leak-testing after installation is about confirming the piping and components are airtight before the system is put into service. The safest and most effective way for flammable-refrigerant systems is to pressurize the system with an inert gas and then check for leaks using appropriate detection methods, documenting the results. Using inert gas during the test prevents ignition hazards that could occur if a leak were discovered with a flammable refrigerant. Relying on visual inspection alone can miss hidden leaks, and a hot water test or a simple soap-bubble test by itself isn’t reliable enough to prove integrity. A proper test combines a pressure procedure with suitable leak-detection methods (such as calibrated detectors and/or corroborating soap-bubble checks at joints) and then records the test pressure, duration, findings, and acceptance status to show the system passed the leak-tightness requirement.