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Component of collector, which absorbs solar radiation.

Absorber plate
An essential planar ( flat) from absorber.

The ratio of radiation energy absorbed by a surface to that of the radiation falling on the surface.

The process in which one substance is taken into the body of another substance, termed the absorbent. An example is the absorption of water into the soil.

The quantitative capacity of a water, or water solution, to neutralise an alkali or base. It is usually measured by titration with a standard solution of sodium hydroxide, and expressed in terms of its calcium carbonate equivalent.

Activated carbon
A granular material usually produced by the roasting of cellulose base substances such as wood or coconut shells in the absence of air. It has a very porous structure and is used in water conditioning as an absorbent for organic matter and certain dissolved gases. Sometimes called "activated charcoal".

Activated silica
A material usually formed from the reaction of a dilute silicate solution with a dilute acid, and used as a coagulant aid.

Where molecules of a gas or liquid or solute form a thin film on the outside surface of a material.

An action or process conducted in the presence of air, such as aerobic digestion or organic matter by bacteria.

Air gap
A clear vertical space between a water, or drain, line and the flood level of a receptacle, used to prevent backflow or siphonage from the receptacle in the event of a negative pressure or vacuum.

A group of water-soluble mineral compounds, usually considered to have moderate strengths as bases, as opposed to the caustic or strongly based hydroxides. In general the term is applied to, carbonates, borates, phosphates, and silicates when these are present in the water or solution.

A common name for aluminium sulphate used as a coagulant in water treatment.

Of or relating to the immediate surroundings.

Ambient air
Air space surrounding a solar collector or an other object being considered.

Ambient Temperature (Ta)
The air temperature surrounding the device

Ampere (Amp)
The unit for measuring rate of flow of electrical current: Current (Amps) = Power (Watts) / Voltage (Volts)

A small single-celled animal or protozoan.

A negatively charged ion in solution such as bicarbonate, chloride or sulphate.

Anion exchange
An ion exchange process in which anions in solution are exchanged for other anions from an ion exchanger. In demineralisation for example, bicarbonate, chloride and sulphate anions are removed from solution in exchange for a chemically equivalent number of hydroxide anions from the anion exchange resin. (see also, demineralisation)

Aperture area
Opening through which uncocentrated solar radiation is admitted.

A layer or zone below the surface of the earth, which is capable of yielding a significant volume of water.

Is a chronic medical condition. It has been defined  as a common chronic disorder of the airways that is complex and characterized by variable and recurring symptoms, airflow obstruction, bronchial hyperresponsiveness (bronchospasm), and an underlying inflammation.

The process in which solids are worn down or ground down by friction, often between particles of the same material. Filter media and ion exchange resins are subject to attrition during backwashing, regeneration and service.

A highly poisonous metallic element having three allotropic forms, yellow, black, and gray, of which the brittle, crystalline gray is the most common. Arsenic and its compounds are used in insecticides, weed killers, solid-state doping agents, and various alloys.

Auxiliary heat source
Heat other than solar supplement to output of solar energy system.


Flow of water in a pipe or line in a direction opposite to normal flow; often associated with back siphonage or the flow of possibly contaminated water into a potable water system.

The process in which beds of filter or ion exchange media are subjected to flow opposite to the service flow direction to loosen the bed and to flush out suspended matter collected during its operation.

Are living cells that, in favourable conditions, can multiply rapidly. Harmful bacteria, once inside the body, can release poisons or toxins which make us ill. Diseases caused by bacteria include: food poisoning, typhoid and cholera. We recomend the 2000 Filtration system.

Inhibiting the growth of bacteria.

A substance which releases hydroxyl ions when dissolved in water. Bases react with acids to form a neutral salt and water.

The metric unit of pressure equivalent to approximately 14.5 pounds per square inch (psi).

Base exchange
Ion exchange in which the exchanged ions have positive charges (cations) synonymous with cation exchange.

The ion exchanger or filter media in a column or other tank or operational vessel.

Bed depth
The height of the ion exchanger or filter media in the vessel after preparation for service.

Bicarbonate alkalinity
The alkalinity of water due to the presence of bicarbonate ions.

Biochemical oxygen demand (BOD)
The amount of oxygen consumed in the oxidation of organic matter by biological action under specific standard test conditions. Widely used as a measure of the strength of sewage and wastewater.

Blue Green Algae
Is a phylum of bacteria that obtain their energy through photosynthesis.

Brackish water
Water containing dissolved solids in the range of 1,000 to 10,000 mg/l.

Breakpoint chlorination
A chlorination procedure in which the chlorine is added until the chlorine demand is satisfied and a dip (breakpoint) in the chlorine residual occurs. Further additions of chlorine produce a chlorine residual proportional to the amount added.

The appearance in the effluent from a water conditioner of the material to be removed by the conditioner, such as hardness in the effluent of a softener, or turbidity in the effluent of a mechanical filter. Breakthrough provides an indication that regeneration, backwashing, or other treatment is necessary for further operation.

Often used incorrectly with respect to illumination as a synonym for luminous flux, an objective measurement of the visible power of a light source. The term is correctly used when describing screen brightness in a display or television.

A strong solution of salt(s), such as the sodium chloride brine used in the regeneration of ion exchange water softeners. Also applies to the mixed sodium, calcium & magnesium chloride waste solution from regeneration.

Brown Coal
Brown coal is a group of low ranked coals of which lignite is amongst the most common.  It is seen as the dirtiest/ lowest form of coal as it has a low heat content due, in part, to a greater than 50% moisture content.  It often has a distinctive fibrous structure, indicating little coalification beyond peat.  
It has such "Lignite" and "brown coal" are terms often used interchangeably. Brown coal is a common European term but not used in America. 

A chemical which causes a solution to resist changes in pH, or to shift the pH to a specific value.

A connection or a valve system that allows untreated water to flow to a water system while a water treatment unit is being regenerated, backwashed or serviced. Also applies to a special water line installed to provided untreated water to a particular tap.


 It gives that milky colour to water and can leave a build-up of scale and white tide marks on glassware and cutlery. We recomend 2000 Filtration system 

Campylobacters are small spiral shaped bacteria that are the commonest cause of diarrhoea in Britain.

Materials of or derived from organic substances such as peat or coal.

Carbonate alkalinity
Alkalinity due to the presence of the carbonate ion.

Carbonate hardness
Hardness due to the presence of calcium and magnesium bicarbonates and carbonates in the water; the smaller of the total hardness and the total alkalinity. (See temporary hardness.)

Cancer causing agent.

The negative pole of an electrolytic system.

An ion with a positive electrical charge, such as calcium or magnesium.

Cation exchange
Ion exchange process in which cations in solution are exchanged for other cations from an ion exchanger.

The flow of water or other solution in a limited number of passages in a filter or ion exchanger bed, instead of an equally distributed flow through all passages of the bed. May be due to fouling of the bed and plugging of many passages, poor distributor design, flow rates which are to low, faulty operational procedures, or other causes.

To form a complex chemical compound in which an ion, usually metallic, is bound into a stable ring structure.

Chemical stability
 Resistance to attack by the chemical action; often applied to the resistance of ion exchange resins to breakdown due to the contact with aggressive solutions.

 is the process of adding the element chlorine to water as a method of water purification to make it fit for human consumption as drinking water. Water which has been treated with chlorine is effective in preventing the spread of disease.

Chlorination Disinfection By-Products (CBPs)
Chlorination Disinfection By-Products (CBPs) are strong oxidising agents put into water to eliminate pathogenic microbes and to form a disinfectant residue so water can reach the consumer tap safe from microbial contamination. In some situations Chlorination Disinfection By-Products (CBPs) have been found to be carcinogenic.

A gas, widely used in the desinfection of water and oxidising agent for organic matter, iron, etc.

Chlorine demand
A measure of the amount of chlorine which will be consumed by organic matter and other oxidisable substances in a water before a chlorine residual will be found; the difference between the total chlorine fed and the chlorine residual.

Closed loop
A closed circuit where the fluid is recalculated.

A material, such as alum, which will form a gelatinous precipitate in water, and cause the agglomeration of finely divided particles into larger particles which then can be removed by settling and/or filtration.

Cold feed
start of in coming water supply to a system.

Coliform bacteria (Coliforms)
A group of organisms primarily found in human and animal intestines and waste, and thus widely used as indicator organisms to show the presence of such wastes in water, and the possible presence of pathogenic (disease causing) bacteria.

A general term for a device, which absorbs solar radiation and transfers thermal energy to fluid passing through it.

Collector cover
The transparent or translucent material that covers the absorber of a collector to reduce heat loss and to provide environmental protection.

Collector efficiency
The efficiency of a solar collector measured as the ratio of energy removed by the heat transfer fluid over a specified time period to the total energy falling on the outside of the collector cover under steady sate conditions i.e. when heat removal rate including losses equal to solar energy input rate.

Very fine divided solid particles which will not settle out of a solution; intermediate between a true dissolved particle and a suspended solid which will settle out of solution.

The shade or tint imparted to water by substances in true solution, and thus not removed by mechanical filtration; most commonly caused by dissolved organic matter, but may be caused by dissolved minerals.

Colour temperature (LEDs)
Colour temperature describes whether a light source appears 'warm' or 'c ol' - indicated by the correlated colour temperature (CCT). Lamps with a warm appearance have a CCT of 2700-3000K, and are considered appropriate for domestic settings, while cooler lamps might be 4000K, and are used more often in offices and retail. The higher the colour temperature, the 'cooler' the appearance.

A reddish-brown metallic element that is widely used for water piping. Copper in water can induce acute and chronic intoxication in humans and can cause nausea, vomiting, colic and diarrhoea.

CRI - Colour Rendering Index (LEDs)
Colour rendering index.This is the ability of a light source to show surface colours as they should be, usually in comparison with a tungsten or daylight source. Lamps with poor colour rendering will distort some colours.
Colour rendering is usually indicated by the CIE colour rendering index (CRI or Ra) - a number between 0 and 100, where lower values indicate poor colour rendering and higher ones good colour rendering. CRI only works for approximately white sources. Guidance in the Cibse Code recommends lamps with a CRI of over 80 where accurate colour judgement is required, like in shops or offices. For inspection and colour matching, a CRI of above 90 is recommended.

Boilers that provide domestic hot water and space heating storage.

Combined available chlorine
The chlorine present as chloramine or other derivatives in a water, but still available for desinfection and the oxidation of organic matter. Combined chlorine compounds are more stable than free chlorine forms but are somewhat slower in action.

Combined storage
A single vessel that includes heat sources other that the solar water heating system heat source.

Combination of domestic hot water and space heating storage.

Commissioning engineer
Person responsible for declaring that a fitted system is fit for purpose and safe.

Movement of heat through a medium.

The quality of power to carry an electrical current in water. The conductivity id related to the concentration of ions capable of carrying an electrical current.

The addition of foreign matter to a substance which reduces the value of the substance or interferes with its intended use.

A device that controls the output of color-changing and tunable white lighting fixtures. Controllers typically have software components for configuring fixtures and designing and editing light shows, and hardware components for sending control data to fixtures.

The process of heat or mass transfer through a fluid caused b movement of molecules from cool regions to warmer regions.
Cool White
A description of a range of correlated color temperatures.

Measured in amperes, it is the flow of electrons through a conductor. Also know as electron flow.

Crenothrix polysporta
A genus of filamentous bacteria which utilise iron in their metabolism, cause staining, plugging and taste and odour problems in water systems. (See iron bacteria.)

A pathogenic protozoan organism resistant to chlorine.


Dali (LEDs)
Dali stands for Digital Addressable Lighting Interlace and is a controls protocol agreed by major manufacturers in the lighting industry. It is set out in the technical standard 1EG 62386. The AG-Dali is a working group set up by the manufacturers and institutions in the field of digital lamp and luminaire control to promote Dali technology and applications.

The removal of excess chlorine residue.

Decibels (dB)
A unit of sound. 0-1 being the faintest noise you can hear,60 being normal conversation, 180 is a rocket launching pad (Deafaning sound).

The removal of all ionised minerals and salts both organic and inorganic from water by a two-phase ion exchange procedure. First, positively charged ions are removed by a cation exchange resin in exchange for a chemically equivalent amount of hydrogen ions. Second, negatively charged ions are removed by an anion exchange resin for a chemically equivalent amount of hydroxide ions. The hydrogen and hydroxide ions introduced in this process unite to form water molecules. The term is often used interchangeably with demineralisation.

The removal of ionised inorganic minerals and salts (not organic material) from water by a two-phase ion exchange process similar to deionisation.
Destratification (Thermal)
Thermal destratification is the equalisation of air temperature within a building or enclosed space.

The separation of components of a solution by diffusion through a semi-permeable membrane which is capable of passing certain ions or molecules while rejecting.

Diatomaceous earth
Diatomaceous earth consists of fossilized remains of diatoms, a type of hard-shelled algae. It is used as a filtration aid
is a naturally occurring, soft, chalk-like sedimentary rock that is easily crumbled into a fine white to off-white powder. This powder has an abrasive feel, similar to pumice powder, and is very light, due to its high porosity. The typical chemical composition of diatomaceous earth is 86% silica, 5% sodium, 3% magnesium and 2% iron.

Differential pressure
The difference in pressures at two points in a water system; may be due to differences in elevation, or to friction losses or pressure drops due to resistance to flow in pipes, softeners, filters and other devices.

Differential temperature controller DTC
A device that compares temperatures and controls a circulation pump and /or other devices on the basis of the difference between the temperatures.

Diffuse radiation
Radiation reaching the earth after being scattered in the atmosphere ( by cloud, dust partials ect. ) as well as solar radiation reflected b the ground.

A process in which pathogenic, disease causing, bacteria are killed; it may involve the use of chemical agents such as chlorine.

Is the condition of having frequent loose or liquid bowel movements.

Direct radiation
Radiation received directly from the sun.

Direct system
A system in which the heated water that is to be consumed within a building passes directly through the collector.

Dirty Electricity/ Electrical Pollution
'Clean’ electricity is free from voltage spikes and drops. ‘Dirty’ electricity (DE) has voltage ripples or noise that is outside the ideal sine This is also known as electrical pollution (called transients and harmonics) which can cause electronics to perform poorly, impacting health and appliance performance.
‘Electrical pollution’ (or ‘dirty electricity’) occurs as a result of wires having become conduits for dangerous levels of radio frequency (RF) radiation and other harmful electromagnetic energy.  As you can’t see or smell it, it’s very difficult to identify DE’s presence even when it’s affecting you. Therefore it’s important to understand what causes electrical pollution and what to look for in your everyday environment and home.
Ferrite beads are a simple solution reduce the affects of DE on you and your appliances wherever you go. 
To read more about how it's affecting you and what you can do about it, read our in-depth article.

The separation of molecules into positively and negatively charged ions in water.

Dissolved solids
The weight of matter in true solution in a stated volume of water; includes both inorganic and organic matter. Usually determined by weighing the residue after evaporation.

The process by which water is converted into its vapour state by heating, and the vapour cooled and condensed back to the liquid state and collected. Used to remove solids and other impurities from the water. Multiple distillations are required for extreme purity.

Down stream
Relative position within the movement of water within a building (with the incoming water supply being upstream).

Drain back system 
A system that automatically drains and refills the fluid in the collector.

Drain back vessel
A vessel in drain back system that accommodates the fluid drained back from the collector.

Dry Skin
A loose, unscientific term used to describe the rough, scaly and flaky skin that is dry to the touch and less elastic than normal skin.

Is a disorder of the digestive system that results in severe diarrhea containing mucus and blood in the feces.If left untreated, dysentery can and usually will be fatal.


Escherichia coli, one of the members of the coliform group of bacteria indicating faecal contamination. (see faecal, coliform).

Effective size
A measure of the size of particles of ion exchange or filtration media

The stream emerging from a unit, system or process, such as the purified water from the FW1000.

A fundamental particle found in an atom and which caries a single negative charge. In a neutral atom, the positive charges of the nucleus are balanced by an equal number of negative electrons in the filed surrounding the nucleus. Ions are formed when atoms gain or lose electrons, thus achieving positive or negative net charges.

Electrical Pollution/ Dirty Electricity
'Clean’ electricity is free from voltage spikes and drops. ‘Dirty’ electricity (DE) has voltage ripples or noise that is outside the ideal sine This is also known as electrical pollution (called transients and harmonics) which can cause electronics to perform poorly, impacting health and appliance performance.
‘Electrical pollution’ (or ‘dirty electricity’) occurs as a result of wires having become conduits for dangerous levels of radio frequency (RF) radiation and other harmful electromagnetic energy.  As you can’t see or smell it, it’s very difficult to identify DE’s presence even when it’s affecting you. Therefore it’s important to understand what causes electrical pollution and what to look for in your everyday environment and home.
Ferrite beads are a simple solution reduce the affects of DE on you and your appliances wherever you go. 
To read more about how it's affecting you and what you can do about it, read our in-depth article.

The stripping of ions from an ion exchange material or absorbent by other ions, either because of greater affinity or because of much higher concentration.

The ration of energy emitted from particle surface compared with the energy emitted from a black body emitter at the same temperature.

Endocrine System
The endocrine system is made up of a series of ductless glands that produce chemical messages called hormones.

End point
Defined as the position in the filtered water run where the concentration of the contaminant in the effluent of the filter exceeds the concentration applicable to the rating of the unit.

The United States Environmental Protection Agency, a government bodie created to protect human health and the environment.

The abbreviation for 'equivalent per million'.

Evacuated tube collector
A collector employing transparent tubbbing9ussually glass0 with an evacuated space between the tube wall and the absorber (the pressure in the evacuated space is usually less than 1 ascal91pa00.

Exchange velocity
The rate with which one ion is displaced from an ion exchange material in exchange for another.

Extra Low Voltage:(evl):
Electricity that is sub 50 V AC or ripple - free 120 V DC.

A skin condition whereby the upper layer becomes inflamed leading to red, itchy and scaly skin. This disorder may be as a result of an alergic reaction. The 2000 Filtration System can help to reduce these symptoms.


Ferrite Beads
A ferrite bead is a passive electric component that suppresses high frequency noise in electronic circuits. It is a specific type of electronic choke. Ferrite beads employ the dissipation of high frequency currents in a ferrite ceramic to build high frequency noise suppression devices. Ferrite beads may also be called blocks, cores, rings, EMI filters, or chokes.

The effluent liquid from a filter.

Extremely small particles of filtration media formed either in the manufacturing process or as a result of breakdown. A cause of high pressure drop in some filters.

Flat plate collector
A solar collector that employs no concentration of the incident solar radiation and in which the absorber plate is essentially flat.

The agglomeration of finely divided suspended solids into larger, usually gelatinous particles. The development of a "floc" after treatment with a coagulant such as aluminium sulphate.

Flow control
A device designed to limit the flow of water or regenerant to a pre-determinate value over a broad range of inlet water pressures.

Flow rate
The quantity of water which passes a given point in a specified unit of time, often expressed in gallons per minute.

The addition of a fluoride compound to a water supply to produce the concentration desired for the reduction in incidence of dental carries.

Is the reduced form of fluorine. Both organic and inorganic compounds containing the element fluorine are considered fluorides. Fluoride, like other halides, is a monovalent ion (−1 charge) anion. But as the lightest halide, its compounds often have properties that are distinctive.

Fossil fuels
These are an fianite resources made from dead plants and animals subjected to the correct heat and pressure over millions of years. Crude oil, coal and natural gas are all fossil fuels. Humans are using them unsustainably [quicker than they are being replenished], leaving knock-on effects on future generations. As they are also carbon stores (accumulations of 'safe' carbon), when they are burnt and combine with oxygen, CO2 is given off.

Free available chlorine
The concentration of residual chlorine present as a dissolved gas, hypochlorous acid or hypochlorite, not combined with ammonia or in other less readily available forms.

Fully Filled
A system in which the fluid in the system circuit is normally above atmospheric pressure and which has all air removed.


Abbreviation for "grains per gallon"

Glazed Collector
A collector with the absorber platencovored by a transparents or translucent material - the term is usually used in relation to flat plate collectors.

A natural mineral, primarily composed of complex silicates, which possess ion exchange properties.

Gross Collector's Area
The total area of the complete collector excluding any integral mounting brackets or pipe work.


A characteristic of natural water due to the presence of dissolved calcium and magnesium. Hardness is usually expressed in grains per gallon, parts per million or milligrams per litre, all as calcium carbonate equivalent.

Hard Water
Water with a total hardness of one grain per gallon or more as calcium carbonate equivalent.  The water that has a high mineral content (calcium and magnesium), prohibiting the lathering of soap amoungst other things. We recomend the Luxury water softening range.

A measure of pressure at a point in a water system, expressed in bar, psi or in the height of a column of water, which would produce the pressure.

Hydrologic Cycle
The water cycle, including precipitation of water from the atmosphere as rain or snow, flow of water over or through the earth, and evaporation or transpiration to water vapour in the atmosphere.


Immune Deficiency Syndrome
A serious (often fatal) disease of the immune system transmitted through blood products especially by sexual contact or contaminated needles.

Incident Radiation
Radiation falling upon or striking a surface.

Incident System
A system in which a heat transfer fluid transfers the energy from the collectors to the storage by means of separate primary circuit and heats the hot water store via a heat exchange coil in the circuit.

The water entering a system or component.

Inorganic Matter
Matter, which is not derived from living organisms and contains no organically produced carbon; includes rocks, minerals and metals.

person who assembles and fits components into a solar domestic hot water system.

A means of control, which prevents a device from operating unnecessarily

An atom, or group of atoms, which function as a unit, and have a positive or negative electrical charge due to the gain or loss of one or more electrons.

Ion Exchange
A reversible process in which ions are released from an insoluble permanent material in exchange for other ions in a surrounding solution.

The rate at which radiant energy falls on a surface -usually measured in watts per square metre (W/m2).

The energy that falls on the surface in a specific time period, often and hour, a data or a year- normally measured in Wh/m2.

Iron Bacteria
Organisms, which are capable of utilising ferrous iron, either from water or from steel pipe, in their metabolism, and precipitating ferric hydroxide in their sheaths and gelatinous deposits.

Irritable Bowel Syndrome
A chronic disorder characterized by motor abnormalities of the small and large intestines, causing variable symptoms including cramping, abdominal pain, constipation, and diarrhea. Also called irritable colon, spastic colon.
Jackson Turbidity Unit
(JTU) An arbitrary unit of turbidity originally based on a suspension of a specific type of silica with the turbidity measured in a Jackson candle Turbidimeter.


KDF 55 Media
KDF 55 Media is constructed of finely granulated Copper and Zinc alloys. The combination of the two alloys creates a chemical reaction called Redox (oxidation-reduction). The KDF process removes electrons from contaminants such as Chlorine making them harmless. KDF 55 media was designed to specifically remove Chlorine, heavy metals and microbiological contaminants.
kWh (kiloWatt-hour)
The kilowatt-hour is a unit of energy equal to 1,000 watt-hours. That's what a 1,000W device uses in one hour - or what a 1W device uses in 1,000 hours. It's the unit that your electricity bill is counted in.

Kelvin is a unit of measurement for temperature and is used to measure the colour temperature of light. Kelvin measurements over 5000 are considered to be cool colours, while measurements between 2700 - 3000 K are considered to be warm colours.


Langelier's Index
A calculated number used to predict whether or not a water will precipitate, be in equilibrium with, or dissolve calcium carbonate.

Is a main-group element with symbol Pb  and atomic number 82. Lead is a soft, malleable poor metal, also considered to be one of the heavy metals.

A Light Emitting Diode is a semicoductor diode that glows when voltage is applied.

The Lighting Energy Numeric Indicator - a measure of the energy predicted to be used by the lights in a building, taking into account daylight, occupancy, operating hours and controls.
Leni, which is recognised in the proposed new Building Regulations for Enqland, is much more nuanced as a predictor of energy use than simply measuring the efficiency of luminaires. Leni knows, for example, that a building in John O'Groats will have to use a little more lighting energy than an identical building at Land's End, because the availability of daylight will differ.

Brown coal is a group of low ranked coals of which lignite is amongst the most common.  It is seen as the dirtiest/ lowest form of coal as it has a low heat content due, in part, to a greater than 50% moisture content.  It often has a distinctive fibrous structure, indicating little coalification beyond peat.  
It has such "Lignite" and "brown coal" are terms often used interchangeably. Brown coal is a common European term but not used in America. 

Lime scale
Hard water scale containing a high percentage of calcium carbonate.

Measures a LED luminaire as a whole system. Approved by the Illuminating Engineering Society of North America (IESNA).

Amount of energy of power re required from a system.

Light output ratio - the percentage of light emitted from the light source that makes it out of the luminaire. An LOR of 70 means 30 per cent of the light from the lamp is lost inside the reflector and light fitting. There is some debate about how to apply LOR to LED luminaires because of the directional nature of light emitted by LEDs.

The lumen (symbol: lm) is the SI unit of luminous flux, a measure of the power of light perceived by the human eye.

Lux (symbol: lx) is a measure of the light arriving on a surface. Lux is the international unit of illuminance and luminous emittance, and measures luminous flux per unit area.
Illuminance is a measure of how much luminous flux is spread over a given area.

A mineral that is essential for growth but too much of it in water can have such side-effects as leaving deposits on boilers.  One of the elements making up the earth's crust, the compounds of which when dissolved in water combine with calcium to make the water hard.

Manganese Greensand
Greensand which has been processed to incorporate in its pores and on its surface the higher oxides of manganese. The product has a mild oxidising power and is often used in the precipitation of iron, manganese and/or hydrogen sulphide and their removal from the water.

A semi-permeable barrier which allows the passage of water. Commonly used reverse osmosis membranes include cellulose acetate, cellulose triacetate and aromatic polyamide polymers.

The abbreviation for milligrams per litre.

A linear measure equal to 1/milion of a metre.

Microgram per litre (ug/l)
A unit of concentration of matter used in reporting the results of water analyses. Also referred to as parts per billion (ppb).

Is a neurological syndrome characterized by altered bodily perceptions, headaches, and nausea.

Milligram Per Litre (mg/l)
A unit of concentration of matter used in reporting the results of water analyses. Also referred to as parts per million (ppm).

Inorganic (matter not plant or animal) elements that are essential components of all cells.

Causes genes to mutate.


Nephelometric Turbidity Unit (NTU)
An arbitrary unit for measuring the turbidity in water by the light scattering effect of fine suspended particles in a light beam.

Net absorber area
the maximum are of a collector reached by solar radiation.

In inorganic chemistry, a nitrate is a salt of nitric acid with an ion composed of one nitrogen and three oxygen atoms (NO−3). In organic chemistry the esters of nitric acid and various alcohols are called nitrates.

Nitrile rubber, also known as Buna-N, Perbunan, acrylonitrile butadiene rubber, and NBR, is a synthetic rubber copolymer of acrylonitrile (ACN) and butadiene. Its typical uses include; disposable non-latex gloves, automative transmission belts and hoses.


Open vented system
A system in which there is contact by the heat transfer fluid to the atmosphere via a vent pipe and cistern.

Operating pressure
The range of pressure, usually expressed in bar, over which a water treatment device is designed to function.

The process by which water and nutrients are supplied to living cells.  The natural flow of water is from a dilute to a concentrated solution across a cell wall.  Cell walls are natural, selective semi-permeable membranes, which allow certain materials to pass through but reject others.


Parasitic losses
Energy consumed during operation by a systems pump and controls.

An organism that may cause disease.

Pathogenic bacteria.
Bacteria that cause disease are called pathogenic bacteria.

Water that has been treated by passing through a membrane filter.

A logarithmic measure of acidity or alkalinity. pH7 is neutral. Acid solutions have a pH less than 7, alkaline more than 7. Each successive pH unit represents a tenfold change in acid or alkaline nature.

PIR (Passive Infra-Red)
Short for passive infrared. PIR sensors are electronic sensors that measure infrared light radiating from objects in their field of view. It can detect heat from objects that is undetectable by humans.

Point of Entry Treatment
Treatment of an entire household supply at the point of entry.

Point of Use treatment (POU)
Treatment of drinking water at the point of use or immediately prior to the point of delivery. The FW1000 is a point of use device.

Are a particular group of thermoplastic polymers. They are easily worked, moulded, and thermoformed; as such, these plastics are very widely used in the modern chemical industry.

Is a thermoplastic polymer, made by the chemical industry and used in a wide variety of applications, including packaging, textiles (e.g. ropes, thermal underwear and carpets),

Potable water
Water which is suitable for human consumption.

The abbreviation for parts per million.

Pre heat vessel
A contained hot water store which accepts heat from solar domestic hot water system prior to the heated water being heated further by an auxiliary heat source.

Is a chronic, non-contagious autoimmune disease which affects the skin and joints. It commonly causes red scaly patches to appear on the skin.

Is a abreviation for Polyvinyl chloride this is the third most widely used thermoplastic polymer after polyethylene and polypropylene. There are manny uses to  this thermoplastic such as producing pipes,cloth,electric wires.


Emission or transfer of energy in form of electromagnetic waves or particles.

Radiant energy
the quality of energy transferred by radiation.

The ratio of the radiant energy reflected from the surface ton that of the incident radiation.

Raw water
Untreated water or tap water before it reaches a specific water treatment device or process.

Renewal- of the system to bring it back to optimum condition after cycles.

Residual chlorine
Chlorine remaining in a treated water after a specific period of contact time to provide protection throughout a main distribution system.

The term used to designate a synthetic organic ion exchange material such as the high capacity selective anion exchange resin widely used in nitrate removal units. Typical ion exchange resins are small beads ranging from 0.3 to 1.3mm in diameter.

Reverse Osmosis
A process that reverses, by the application of pressure, the flow of water in natural process of osmosis so that water passes from the more concentrated to the more dilute solution through a semi-permeable membrane.

The abbreviation for Reverse Osmosis.

ROHS Directive
The Directive on the restriction of the use of certain hazardous substances in electrical and electronic equipment 2002/95/EC


To reduce the number of bacterial contaminant to safe levels as judged by public health requirements. To make clean and free or inactivation of dirt, filth, and conditions injurious to health. Generally considered to reduce germs count by 50 to 99.9 percent. The USEPA requires that sanitising claim must show a 99.9 percent microbial reduction in 5 minutes.

Scale (limescale)
A hard, chalky, white deposit left on the inner surface of old pipes and similar surfaces once 'hard water' has evaporated. It may also be found on the inside of central heating systems, boilers and kettles.

Sealed system
Where the system is sealed from the atmosphere

Selective surface
A surface whose absorbance, emmitance, reflectance, and transmittance vary with the wavelength of the radiation. Values of absorbance are typically high and radiative emittance low. This decreases radiation losses and increases the efficiency of energy collection, particularly at high temperature.

Silicone Carbide
Silicon Carbide is made up of two minerals extracted from the ground: Silicon and Carborundum. When combined, these minerals form one of the hardest materials on earth, second only to diamond.

Silicon Carbide is able to absorb extreme temperatures and then release heat slowly. It offers some of the best energy efficiencies and low levels of carbon available. It is primarily used in electrical conductors and furnaces thanks to its heat conduction properties.

Sodium (Na)
It doesn't react with soap meaning that you need less of it to lather. It also leaves no white traces on your boiler or central heating system.

A process in which all living organisms are destroyed.

Sodium (NA+)
A metallic element found abundantly in compounds in nature, but never existing alone. Sodium compounds are highly soluble and do not form curds when used with soap or detergents. Many sodium compounds are used in the water treatment industry. Most notable is the use of sodium chloride as a regenerant in the cation exchange water softening process.

Solar Collector
A general term for a device, which absorbs solar radiation and transfers thermal energy to fluid passing through it.

Solar energy
Energy emitted by the sun in the form of electromagnetic energy.

Solar energy
Light and radiant heat energy from the sun that is converted into thermal or electrical energy. This energy may then be used to power your home: for example, by heating your hot water.

Solar fraction
the energy supplied by solar domestic hot water system divided by the total system energy load i.e. heat supplied to the user.

Solar heat exchanger
A device fro transferring heat from the solar primary circuit to the domestic hot water without allowing them to mix. This is typically a heating coil in the hot water cylinder.

Solar noon
Local time of day when the sun crosses the observer's meridian.

Solar radiation
Radiation emitted by the sun.

Radiation Also known as high-pressure sodium lamps, a SON is a gas discharge lamp that uses sodium in an excited state to produce light. SONs produce a yellow light and have poor colour rendering, but they are efficient, often reaching about 1OO lm/W. Higher-powered versions of 600W can reach an efficacy of 150 lm/W. by the sun.

Status of a solar collector or system when no heat is being removed by heat transfer fluid (when, for example, the pump is not circulation.

Standing loses
Energy consumed by the system irrespective of operation (including for example loss of heat energy from pipe work and hot water store).

Natural layering of fluid of different densities.

 A product or activity that may be continued without having negetive long-term effects upon the environment wildlife or humans.


Temporary hardness
Water hardness due to the presence of calcium and magnesium carbonates and bicarbonates, which can be precipitated by heating the water.

Causes birth defects.

Is a chlorocarbon with the formula Cl2C=CCl2. It is a colourless liquid widely used for dry cleaning of fabrics, hence it is sometimes called "dry-cleaning fluid." It has a sweet odor detectable by most people at a concentration of 1 part per million (1 ppm). Worldwide production was about 1 megaton in 1985.

Thermal evacuated tube system
Tubular system specifically designed to absorb sunlight to create heat. It has many benefits over a flat collector: a large surface area means that they more easily attain higher temperatures and can even collect when it is cold outside. Their shape also means that they capture more solar energy in the mornings and evening, enabling them to collect more evenly throughout the day, meaning less storage is needed.

Thermosyphon system
A system  which uses only density changes within  the  heat transfer fluid to achieve  circulation
Suspended solids

The minimum value at which an effect or substance can be detected.

Total Organic Carbon. The total carbon content of particulate and dissolved organic matter in water.

Total Dissolved Solids (TDS)
The total amount of particulate and dissolved solids in a solution, usually measured in mg/l. The ionic components of the TDS may also be measured as conductivity or resistivity.

Trace elements
Elements that are essential for healthy growth but are only required in miniscule amounts. The 1000 Filtration System makes certain to leave in these trace elements, which include calcium and magnesium.

A condition caused by the presence of suspended matter and/or absorption of light rays.


Ultraviolet sensor
The physical sensing system used to measure the intensity of ultraviolet light transmitted.
Unglazed collector
A solar collector with the front surface of the absorber plate exposed to the surrounding air.

Relative position within the movement of water with in building (being at or close to the incoming water supply).

Useful energy
The solar energy, after, that reaches the hot water store.


Volatile Organic Carbon (VOC)
Dissolved organic matter which will be driven off as a gas when water is heated.


This is the unit for circuit watts - the number of watts used to power an entire circuit. This differs from the usual watt which refers to watts per luminaire.

Water hammer
A shock wave or series of waves produced by the abrupt acceleration or deceleration of water flow due to inertia. Water hammer may produce instantaneous pressures many times the normal pressure.

Water table
The level of the top of the zone of saturation, in which free water exists in the pores and crevices of rocks and other earth strata.

WEEE (Waste Electrical and Electronic Equipment)
This includes old fridges and fax machines as well as lamps and luminaires. An EU directive of 2003 defines WEEE and sets out how you are and aren't allowed to dispose of it. Recycling schemes such as Lumicom and Recolight help manufacturers of lighting products comply with regulations. The rules on WEEE are set to get tougher thanks to a new directive agreed in Europe (but not yet incorporated into UK law).


Any of the by-products of industrial or chemical processing that have estrogenlike effects.


Zicron (including hyacinth or yellow zircon) is a mineral belonging to the group of nesosilicates.