A _______ measures the amount of delivered pressure to an appliance with no demand to ensure that the regulator will shut off the flow or propane when the appliances are not in use.

• A. Lock up test
• B. Flow test
• C. Pressure test
• D. Temperature test

Answer: (A)

The main idea here is whether the regulator stops delivering gas when there’s no demand. A lock up test checks that the regulator will shut off flow once appliances aren’t drawing any gas. In practice, you close the appliance valves and watch the delivered pressure; if the regulator is working correctly, the pressure should fall to zero or near zero when there’s no demand, showing the flow has been shut off automatically. This protects against unwanted gas flow and buildup when appliances aren’t in use.

Flow testing, by contrast, looks at how much gas is delivered under active demand, not whether the regulator stops flow when demand drops. A pressure test focuses on the system’s ability to hold pressure or detect leaks, not specifically the regulator’s shut-off behavior at zero demand. Temperature testing isn’t related to delivering or regulating gas at all.