Glossary



All-in-One Power Shower
A product which houses a pump and some form of integrated shower control. It needs a low pressure cistern fed supply of stored hot and cold water. Popular models includes the Aqualisa AQUASTREAM and the Mira EVENT or EXTREME

Back-to-wall
The cistern is separate from pan and concealed behind a wall or inside fitted furniture. This can look very streamlined and can be an effective and economical use of space in a small bathroom.

Backflow
Means a flow in a direction contrary to the intended normal direction of flow.

Bar
A unit of measurement of water pressure approximately equivalent to a column of water 10m high or 14.5 lbf/in2 or 100 kPa. per bar. 0.1 bar is equivalent to approx three feet vertical height of water pressure

Body Jets
Wall mounted sprays usually installed in multiples.

Body Showers
See Body Jets.

Body Sprays
See Body Jets.

Built-in
A valve installed where the body is recessed in the wall.

Built-in / Back-to-wall
Some specially designed bathroom furniture conceals the cistern, supports the basin and hides pipework, creating storage space into the bargain. Easy to clean and great for compact or family bathrooms. The WC and bidet may be described as 'back-to-wall'. See also Wall Hung

Ceramic disc taps / technology
Taps which can be turned on or off with just a quarter turn. Ceramic discs inside the tap create a watertight seal and drip-free 'off' position.

Ceramic Disc Valve
A valve where the functional parts are highly polished ceramic components which slide across and seal against each other to control water flow (and sometimes temperature).

Check Valve
A plumbing fitting designed to allow water flow in one direction only.

Cistern
Means a fixed container for holding water at atmospheric pressure. It is normally fitted with a float operated valve and warning pipe

Close coupled WC
The underside of the cistern rests directly on the back of the WC bowl creating a compact unit with low overall height. Some contemporary designs appear almost like a single item.

Cold Water Storage Cistern
A fixed container for holding water at atmospheric pressure usually used for providing a feed to a vented domestic hotwater cylinder. It can also be used to provide a vented cold supply to terminal fittings.

Combination boiler
A combi is so called because it combines both a central heating boiler and a water heater into one compact, self-contained and economical unit. Unlike a conventional heating and hot water system, a combi does not store hot water. Instead it heats water directly from the cold mains. This is more energy-efficient and can considerably reduce hot water costs, which can account for up to 60% of a typical domestic fuel bill.

Concealed
See Built-in.

Deck mounted taps
Sit on the edge of the basin or bath. (as opposed to being wall mounted)

Double Ended Pump
See Twin Pump.

Dual flow taps
Hot and cold supplies are of different pressures. They come from a single spout but are not pre-mixed - beware of scalding.

Dual flush
The cistern offers the option of a water saving or full volume flush. Current UK flush volumes are 4 and 6 litres of water.

Electrical Heating Element
A component used in an instantaneous electric shower to heat the water.

Fixed Shower Head
An over head fixed height shower head.

Flow Limiter
See Flow Regulator.

Flow Regulator
A device with moving parts which responds to variable inlet pressures to control flow at a reasonably constant rate. These are subdivided into two types: a) Fixed manufactured in a range of predetermined flowrate settings. b) Variable manually adjustable to provide different flowrate settings.

Flow Restrictor
A device with no moving parts which restricts flow. Unlike a flow regulator it does not keep a constant flow when the supply pressure varies.

Fused Spur
A branch off an electrical ring main to a double pole switched connection box fitted with a fuse to enable the connection of a fixed electrical appliance.

Hand Shower
A showerhead attached to a flexible shower hose also termed a shower handset

Handset
See Hand Shower.

Handset Holder
See Wall Bracket.

Header Tank
See Cold Water Storage Cistern.

Hose Restrainer
A device which restrains a shower hose to prevent immersion of the hand shower.

Hose Retaining Ring
See Hose Restrainer.

Hot Water Cylinder
Means a cylindrical closed vessel capable of containing water under pressure greater than atmospheric.

Impeller
The internal part of the pump that is driven by the motor, and is used to move the water.

Inlet Pump
See Twin Pump.

Instantaneous Electric Shower
A shower that electrically heats the water whilst the water is passing through it.

Instantaneous Gas Water Heater
An appliance which heats water on demand whilst the water is passing through it.

Integrated Power Shower
See All-in-One Power Showers.

Low level / High level WC
The cistern and WC pan are separated by a flush pipe and the cistern is fixed either high on the wall or (relatively) low.

Manual Mixing Valve
A device which mixes hot and cold water but does not compensate for variations in the temperature or pressure of the incoming water supplies and needs to be adjusted manually.

Modulating Instantaneous Gas Water Heater
An instantaneous gas water heater or boiler which is fitted with a gas control mechanism to vary the heat input and produce a relatively stable domestic hot water temperature, often termed fully modulating. Step modulating: Gas controlled heat being less able to maintain a constant output temperature under varying flow rate conditions.

Monobloc taps
Hot and cold water are mixed and delivered through a single spout.

Multi Point (instantaneous water heater)
An instantaneous water heater which can supply water to more than one outlet, but not usually simultaneously.

Negative Head
If the cistern is below the level of the shower head a gravity flow of water will not occur. A pump with special switching can be used to obtain a flow of water.

Non-Return Valve
See Check Valve.

Offset corner bath
A design with one side longer than the other. Useful when a standard corner bath would be too large for the space available.

Open Outlet Flow Rate
Maximum potential flow rate from mixing valve without shower fittings attached.

Outlet Pump
See single pump.

Parking Bracket
See Wall Bracket.

Porcelain enamelled steel bath
The ultimate in durability and rigidity - and guaranteed for 25 years. (UK and Ireland) Choose from standard or heavy gauge.

Pressure Balancing Mixing Valve
A pressure balancing compensatory shower mixer valve designed to maintain a constant shower temperature under variable inlet pressures but maintained inlet temperatures.

Pressure Compensating
See Pressure Balancing Mixing Valve.

Pump Hose (or Flexible Connector)
A flexible pipe that connects the pump to rigid pipework.

Quarter turn taps
Taps which can be turned on full by rotating the handle just 90 degrees.

Recessed
See Built-in.

Right Angle connector
See Wall Outlet Connector.

Riser Rail
See Wall Bar.

Semi-recessed basin
A fitted basin which is 'semi-recessed' into a vanity unit or a range of units. May be more comfortable to bend over than a fully recessed vanity basin.

Servicing Valve
A valve for shutting off the flow of water in a pipe connected to a water fitting to facilitate the maintenance or servicing of that fitting.

Shower Head
Any device designed to produce a spray pattern.

Shower Hose
A flexible pipe that connects between the shower head and the shower control.

Showering Station
See Wall Bracket.

Single Ended Pump
See Single Pump

Single flow taps
Hot and cold supplies come ready mixed from a single spout.

Single lever taps
A single monobloc tap with a lever handle controls both water flow and temperature.

Single Outlet Pump
See Single Pump.

Single Pump
A pump used for drawing water from a mixing valve for delivery to a shower.

Slide Bar
See Wall Bar.

Standing Pressure
See Static Pressure.

Static Pressure
The water pressure existing at a fitting when no flow is taking place.

Strainer
A screen to prevent debris from entering a water fitting.

Supply Pipe
A pipe conveying mains cold water around the building.

Supply Stop Valve
A valve used to isolate the mains cold water supply within a building.

Temperature and Pressure Release Valve
A Relief valve fitted to unvented cylinders to vent excessively hot water and to relieve excess pressure safely to atmosphere.

Thermal Storage Hot Water System
A hot water system where cold mains pressure water is heated (instantaneously) as it passes through a heat exchanger surrounded by a stored volume of hot water.

Thermostatic Mixing Valve
A device which mixes hot and cold water and automatically compensates for variations in the temperature and, or pressure of the incoming water supplies, to maintain a selected blend temperature.

Three hole mixer taps
Separate hot and cold handles blend water through a central spout. (requires 3 holes in the bath, basin, wall or countertop to which it is fitted)

Twin Ended Pump
See Twin Pump.

Twin Impeller Pump
See Twin Pump.

Twin Pump
A pump with two independent inputs and outputs typically used for boosting both hot and cold supplies to a shower mixer and/or other terminal fittings (Two single pumps can be used in place of a twin pump).

Unvented Domestic (hot water cylinder)
A plumbing system where the cold feed is taken directly from the mains to provide a high pressure hot water supply. There is no open vent to atmosphere. (Popular model = MEGAFLOW)

Vanity basin (or Vessel Basin)
A fitted basin which is completely surrounded by a counter top (or even sits on a countertop = Vessel or Countertop Basin).

Wall Bar
A vertical rail assembly to allow height adjustment of a hand shower.

Wall Bracket
Fixed device for holding hand showers.

Wall Elbow
See Wall Outlet Connector.

Wall hung
The WC cistern is concealed behind a wall or inside fitted furniture and the pan juts out from the wall, above the floor. Basins and bidets can also be wall hung. This makes for a clean, minimal look, as well as for easy cleaning. This is a European look which is becoming more popular in the UK. For ease of installation a wall hung WC, Bidet or Basin is often fitted to a hidden frame such as a GROHE RAPIDSL

Wall Outlet Connector
Wall mounted device to enable a flexible shower hose to be connected to concealed pipework.

Wrap-over seat
The WC seat is designed with a lid that 'wraps over' the seat ring producing a stylish, easy-to-clean, comfortable design.