The concentration is calculated on the volume of water that is in the well. The concentration must be at least 200 milligrams of chlorine per litre of water present in the well and must be left in the well for at least 12 hours to ensure any bacteria present are.
idles; idled; idling. Learner's definition of IDLE. 1. of an engine or vehicle: to run without being connected for doing useful work. [no object]. She left the engine idling for a few seconds before she turned it off. The cars idled in traffic.
An idle air control valve, also called an idle air sensor control motor, is an electrically operated valve that controls the amount of air that bypasses the throttle plate in cars with a fuel injection system [source: Autozone ]. This causes the idling speed of the engine to change as needed.