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Plumbing Repair Glossary

Your home's plumbing system can be intimidating. Lowe's has all the information you need to make repairs and updates on your own, without being overwhelmed.

Plumbing Repair Glossary

Techniques for Plumbing

Dry Fit:  connecting pipe without adhesive for the purpose of checking measurements

Roughing In: positioning and installing supply and drain-waste-vent pipes in walls and floors, while the walls and floors are unfinished. Roughing in does not include connecting fixtures.

Solvent Welding: joining two things together by using a solvent, which softens the materials, then evaporates after adhering them

Snaking: clearing blocked drains by pushing and twisting a drain-and-trap auger

Sweating: connecting copper pipe and fittings with soldered joints

Tapping In: connecting new pipes to existing plumbing line to serve a new fixture

Threaded Connections: connecting pipe together by screwing them in using the spiral ridges on the ends of the pipes

Valve Dressing: grinding a worn valve seat with a special tool to stop drips in compression faucets

Pipe Fittings

Adapter: a fitting that joins pipes made of different materials or sizes

Bushing: a fitting that joins pipes made of different sizes, threaded inside and out

Cap: a fitting that covers and seals the end of a pipe

Closet Flange: an anchoring ring that attaches to the closet bend and is secured to the floor

Coupling: a fitting that makes a connection between two straight runs of pipe

Ell: an elbow joint with hubs on both ends used to make an angled connection between two straight runs of pipe

Flange: the end of a pipe that has an extended rim to give a finished appearance

Hub: the wide end of a fitting that allows insertion of a pipe for making a joint

P Trap: a curved section of pipe that prevents sewer odors from escaping into the house. It is required on all fixtures with a drain

Street Ell: an elbow joint with a hub on one end used to make an angled connection between pipe and a fitting with a hub

Tee: a T-shaped fitting that joins three lengths of pipe, two lengths in line with each other and the third length perpendicular to the first two

Union: a three piece fitting that joins two sections of pipe, while allowing them to be disconnected without having to cut the pipe

Wye: a Y-shaped fitting that joins three lengths of pipe in branch fashion

Supply System Components

Air Chamber: an extra length of pipe installed vertically on a supply line near a fixture to prevent water hammer.

Branch Line: a supply pipe that carries water to an individual fixture

Compression Fitting: a connector used on copper and plastic pipe, composed of a threaded body, a compression nut and a compression ring. It forms a watertight seal when the body and nut are tightened, squeezing the ring around the pipe.

Riser: a supply pipe that runs vertically from floor to floor

Service Pipe: the pipe that delivers cold water to the house from a water main or well

Shut-Off Valve: a valve that cuts off water to one or more fixtures, allowing repairs without shutting off the supply system for the entire house

Trunk Line: the main cold-water supply pipe within the house

Waste System Components

Branch Vent: a pipe connecting the drain of a single fixture to the vent stack

Cleanout: an opening, closed by a removable plug, that provides access to a drain or sewage pipe for clearing blockages

Drain Trap: a U-shaped passage at a fixture or in a drain line that stays filled with water to keep sewer gases from escaping from the drain into living spaces

Main Drain: the slanting pipe in the basement or crawl space that carries wastes to a sewer or septic tank; also called building drain

Septic Tank: a buried tank where wastes from the drain system are decomposed and purified

Soil Stack: a large vertical pipe that carries wastes from fixture drains to the main drain

Vent Stack: a large vertical pipe that projects above the roof; connected to the soil stack. it vents sewer gases from the soil stack, preventing the gases from entering the living space

Plumbing Problems

Galvanic Corrosion: corrosion caused by natural chemical interaction between different metals

Siphoning: suction from dropping water pressure that draws water or waste through the lines

Water Hammer: the banging of pipes against hard surfaces when water flow is suddenly cut off at a fixture

Plumbing Safety

Hydrostatic Testing: a test using noncompressible liquid under pressure at a level equal to or greater than the maximum pressure that will be utilized when in use, such as in steam boilers. This test is used to find leaks.

Temperature and Pressure Relief Valve: this valve releases water if the temperature or pressure inside the water heater tank becomes too high, preventing the water heater from becoming dangerous and exploding

Scalding: this is a major concern with water heaters. The temperature of the water can get high enough that it scalds the skin upon first coming out of the tap. The elderly and children are the most susceptible to this danger. Temping valves are used to keep this from happening.

Legionella: this is a bacteria that tends to grow in hot water heaters in which the water is not hot enough to kill them. It leads to Legionnaire's disease, which has caused many deaths. The best means of preventing this bacteria from growing in a hot water system is to set the temperature above 122° F.

Cross Connection: this occurs when is a chance that drinking water and non-potable wastewater could mix. This most often happens when the pressure in the system changes or is turned off and non-potable water is drawn into the supply system.