Plumbing glossary H

Is your plumber confusing you with a load of H-words? Read our plumbing glossary to discover the meanings behind the jargon.

Hanger – a device used to support pipes

Hard water – natural water containing impurities in various proportions – traditional hardness is a measure of calcium or dissolved solids in a solution, measured in parts per million

Head – the pressure of water or steam in a closed system – it represents the difference in the gravitational force exerted by a liquid at two different depths

Heat exchanger – a heat transfer system

Heat trap – restriction of heat loss through water connections to a tank

Hermetic – completely sealed, especially against the escape or entry of air

Hertz – a measure of frequency wherein one hertz equals one cycle per second

Hex key – allen wrench

Hold down – a type of pipe anchor consisting of a U-strap bolted at either end on to a horizontal plate

Hollow-jet valve – a valve having a closing member that moves upstream to shut off the flow

Hose bibb – term used for sillcock

HP – horsepower

Hydraulic pressure – pressure that exists in a system containing non-compressible liquid

Hydrolysis – the reaction of a salt with water to form an acid and a base

Hydronic – system of forced hot water

Hydrojet – cold inlet tube designed to reduce sediment build-up and increase efficiency in a water heater

Hydroxyl – the chemical group of ion, which is neutral or positively charged

Hygroscopic – attracting or absorbing moisture from the air changed or altered by this absorption

We’re working our way through the plumbing alphabet; so don’t forget to bookmark our page to keep up with the lingo.

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