Why purge gas from the system before leak testing?

• A. To cool the regulator.
• B. To remove air that could give false leak indications and to ensure accurate testing.
• C. To add extra propane.
• D. To lubricate joints.

Answer: (B)

Purging clears the line of air so the leak test is accurate. If air remains in the system, it can interfere with the detection method—whether you’re using a tracer gas detector or a soapy-bubble test—by diluting or masking the gas you’re trying to find. That can lead to false readings: you might think there’s a leak when there isn’t one, or miss a real leak because the test isn’t reacting to the propane properly. Replacing the air with purge gas gives a consistent, known gas environment, so leaks show up reliably and the test results reflect the true condition of the system.