| "M" Tubing |
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An industry standard for copper tubing defined by the tube wall thickness, identified by a "red" stripe. |
| MC Tank |
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Acetylene tank holding 10 cu.ft. of gas, used for plumbing, once used to fuel motorcycles. |
| MCL |
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Maximum Contaminant Level The maximum level of a contaminant allowed in water by federal law. Based on health effects and currently available treatment methods. |
| MHT |
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Male Hose Threads (threads on outside of connection) |
MIP |
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Male Iron Pipe Connection. Standard external threads on pipe and fittings. |
| MNPT |
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This refers to the male pipe thread, in which the threads are on the outer side on the connection fitting. |
| MPX |
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Male Pipe Swivel Connection |
| Macerator |
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A device installed in a drain line between a toilet and the soil stack to reduce solids to liquid form. |
| Main |
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The primary artery of supply of the water supply or drain system in which all the branches connect. In the case of drains, known as the Main Vent. |
| Male Fitting |
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Fitting that is inserted into another fitting. |
| Male Threads |
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Threads on the outside of pipes and fittings. |
| Malleable Fittings |
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Fittings made of cast iron. Metal which is soft and pliable. |
| Manhole |
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Access opening to a hole, usually with a cover, through which a person may enter a sewer, boiler, drain, etc. (usually round to prevent the cover from falling into the opening). |
| Manifold |
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A fitting that connects a number of branches to the main; serves as a distribution point. |
| Manifold Pressure |
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The gas pressure in an appliance manifold upstream of the burner orifices. |
| Manifolded Installation |
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Paralleling of water heaters for large hot water demand applications. |
| Mapp Gas |
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A colorless, flammable gas made by combining liquefied petroleum gas with Methylacetylene-Propadiene. It is a stable, non-toxic fuel used in brazing and soldering. |
| Mechanic's Lien |
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A lien obtained by an unpaid subcontractor or supplier through the courts. When enforced, real property - such as your home - can be sold to pay the subcontractor or supplier. |
| Mechanical Controls |
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Dials, slides, switches, knobs, buttons, and so forth used to operate ranges, ovens and cook-tops. |
| Mechanicals |
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The wiring, plumbing and heating and cooling systems in a building; also the components with moving parts such as furnaces, plumbing fixtures, etc. |
| Metal Fatigue |
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A breakage of the metal caused by the bending and flexing or the expansion and contraction of a metal part beyond its endurance limit. |
| Meter Tailpiece |
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An adapter connecting a water meter to the water supply line. |
| Meter Tile |
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The cylindrically shaped casing that forms the pit to hold a water meter. It's usually made of plastic. |
| Micron |
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A unit of measure, one thousandth of a meter. Used to describe the pore size of filters. |
| Mini-Widespread |
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A special style of bathroom lavatory faucet having separate spout and handles, but small enough to fit 4 inch center-to-center faucet holes. |
| Minimum Run Time |
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The minimum length of time that the pump should run while refilling the pressure tank. |
| Mission Coupling |
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A neoprene flex coupling, connecting PVC to PVC or clay to PVC. |
| Mixer |
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The portion of a burner where air and gas are mixed before delivery to the burner ports. |
| Mixing Valve |
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Mixes hot and cold water to achieve a specified delivery temperature. |
| Moenstone ® |
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A blend of ceramic-like quartz (70%) and acrylic polymer (30%) that is impervious to chips or water spots. |
| Monitor Cover |
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The cast iron lid that fits over a flange casting which is mounted on meter tile in a water meter pit. It consists of an outer lid, an inner lid, and the flange casting in one or two pieces. |
| Monoblock Faucet |
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A single-handle faucet, usually a lever. |
| Most Probable Number (MPN) |
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The term used to indicate the number of organisms which, according to statistical theory, would be most likely to produce the results observed in certain bacteriological tests; usually expressed as a number in 100 ml of water. |
| Multiport Valve |
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Rotary type backwash valve. Can replace up to 6 regular gate valves. Serves various functions. |
| Multi-Stage Pump |
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A pump that has more than one impeller. |
| Municipal Water |
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Water supplied by a city for public use; tap water. Usually held in a reservoir. |
