What device is located at the bottom of a tank for flushing toilets and similar fixtures?

The flush valve is a crucial component located at the bottom of a toilet tank, serving the primary function of releasing water from the tank into the bowl when the toilet is flushed. This mechanism is designed to initiate the flushing process, allowing gravity to pull the water down and clear waste from the bowl. The flush valve is typically activated by the flush handle, which lifts a flapper or exposes an opening in the valve, permitting the stored water to flow rapidly into the bowl.

In contrast, the other options refer to different parts of the plumbing system with distinct functions. The shut-off valve is used to control the flow of water to the toilet, allowing for maintenance or repair without disturbing the water supply. The tank filler, often part of the fill valve assembly, refills the tank after a flush by allowing a controlled flow of water into the tank. The overflow valve is a safety feature that prevents water from overflowing the tank in case the fill valve malfunctions or fails to shut off when the tank is full. Understanding the role of the flush valve is vital for diagnosing issues related to flushing performance and ensuring that toilets function efficiently.