Plumbing Terms Glossary

Customer Plumbing definitions

Helpful words and phrases that heating and plumbing engineers tend to use:

Ballcock: The fill valve that controls the flow of water from the water supply line into a gravity-operated toilet tank. It is controlled by a float mechanism that floats in the tank water. When the toilet is flushed, the float drops and opens the ballcock, releasing water into the tank and/or bowl. As the water in the tank is restored, the float rises and shuts off the ballcock when the tank is full.

Air Lock: Blockage in the flow of water in the heating or hot water system, especially on the suction side of a pump caused by an air bubble in the line.

Bleed: To drain a pipe, tube, or hose of excess air by opening a valve at the end or systematically removing the air by force or suction.

Expansion Tank: A tank designed to absorb excess pressure due to thermal expansion

Float Ball: The floating ball connected to the ballcock inside the tank that rises or falls with changing water levels in the tank, and actuates or shuts off the ballcock as needed.

Plunger: An instrument usually with a rubber head, used to create suction in a drain line or a toilet to push a clog through the line.

Thermostatic Valve: A valve with automatic temperature control. When temperature or pressure fluctuations occur at the water inlets, a thermal actuator adjusts the hot and cold ratio to maintain the original temperature setting.

Trap: Curved section of drain line that prevents sewer odours from escaping into the atmosphere. All fixtures that have drains must have a "P" trap installed. A toilet is the only plumbing fixture with an "S" trap.

Locksheild valve: This is a valve  generally used for balancing. Normally find them on a hot water cylinder or one end of a radiator.

Stop cock: Incoming mains stop cock to turn the mains water off to the house. 
Bleed key: A special key that you can buy from most hardware shops that allows you to bleed the air out of your radiators

Flue: You will find  this on top or on the back of a boiler. This is where the boiler fumes (exhaust) is extracted out of the boiler to the outside of the property.

Condense pipe:  All new modern boilers are condensing and require a white plastic  pipe that runs to a waste or drain. This will allow the boiler to condense and work efficiently.

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