Fill Valve (Ballcock)
A fill valve, the modern replacement for the old ballcock, is the tank part that refills a toilet after a flush and shuts off when the water reaches the set level.
The fill valve is the tall assembly on the left side of a toilet tank that lets fresh water in after each flush and stops it at the right level. Older toilets used a ballcock, a valve operated by a float ball on the end of a long brass arm; most fill valves today use a cup-shaped float that rides up and down the valve body, which is quieter and easier to adjust. When the tank empties, the valve opens; when the float rises back to its set height, it shuts the water off.
Homeowners meet the fill valve when a toilet runs constantly, fills too slowly, makes a hissing or whistling noise, or will not fill at all. A worn fill valve may fail to shut off, sending water up the overflow tube and down the drain, or it may clog with sediment and trickle. It is one of the two parts, along with the flapper, that homeowners replace most often, and it drops in with a single nut under the tank.
Setting the water level is part of the job: too high and water pours into the overflow tube, too low and the bowl flushes weakly. The fill valve also feeds a small refill tube into that overflow tube to restore the bowl’s standing water after each flush, a detail people often forget to reconnect.
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- Faucet Cartridge : A faucet cartridge is the replaceable inner valve that controls water flow and temperature in a modern single- or double-handle faucet, and the usual cause of a drip.
- Aerator : An aerator is the small screened tip that screws onto a faucet spout, mixing air into the stream to soften the flow, cut splashing, and save water.
- Sillcock / Hose Bib : A sillcock, or hose bib, is the outdoor faucet on the side of a house where a garden hose connects, with frost-proof versions designed to resist freezing.
- Pressure-Balancing / Mixing Valve : A mixing valve blends hot and cold water to a set temperature, and the pressure-balancing version protects a shower from scalding when water is drawn elsewhere in the house.