Red Seal Plumbing Practice Exam

Which of the following describes reduced pressure fall-off?

1. The increase in flow pressure above the no-flow pressure

2. The stabilization of pressure in a closed system

3. The change in the reduced flow pressure below the no-flow pressure required to open the valve

4. The equalization of pressure across a valve

The correct answer is: The change in the reduced flow pressure below the no-flow pressure required to open the valve

Reduced pressure fall-off refers to the decrease in flow pressure below the no-flow pressure that is necessary for a valve to open. This means that the reduced pressure (lower than no-flow pressure) allows for the opening of the valve, rather than the equalization of pressure seen in option D. Option A is incorrect because increased flow pressure would not trigger a reduction in pressure to open a valve. Option B is incorrect because stabilization of pressure does not necessarily involve a decrease in pressure, as is required for reduced pressure fall-off.