Direct System Close Coupled – Cistern Type

Inland and Coastal Areas

The direct system is used where the water quality is good (less than 600ppm Total Dissolved Solids/Minerals).

A direct system is where the water to be used in the household (hot water) is heated by means of solar radiation absorption by the vacuum tubes and directly heats the water in the solar water heater.

In the close coupled system the vacuum tubes are in integral part of the storage tank and the heated water in the tubes rises and heats the water in the tank, known as a thermosyphon system. The system operates according to the basic principles of physics.


The complete Cistern Type Solar Water Heating System is ideal for low cost housing, where homes do not have an electric water heater to supply hot water and in rural areas and homes where electricity is not readily available to heat water. It provides hot water to those who do not have the luxury of having hot water on tap.

Low Pressure Solar Water Heater and Self Filler Tank

  • 304 stainless steel 110lt tank covered in galvanised outer casing. IPX4 rated.
  • The horizontal solar water operates at zero pressure and relies on gravity to feed water to the taps.
  • The self filler tank controls the water flow into the solar water heater. The self-filler tank has a high pressure float ball valve, which allows for a direct connection to the municipal mains supply, without any additional valves.
  • The solar water heater relies solely on solar radiation transmitted via an array of vacuum tubes to heat the water and does not have an electrical element and thermostat as a back-up.

Solar Vacuum Tubes Features

  • Vacuum tubes consist of two glass tubes manufactured from borosilicate glass.
  • The outer glass is transparent allowing light rays to pass through with minimum reflection.
  • The inner glass is coated with a special solar selective coating (Al-N/A1), which provides excellent solar radiation absorption.
  • The tops of the tubes are fused together and the air extracted, which forms a vacuum, which is key to the efficiency of the vacuum tubes.
  • If the vacuum is ever lost, the silver inner coating will turn white.
  • The water is directly heated in the vacuum tubes.
  • Tubes are freeze and hail resistant.


Low Pressure Solar Water Heater and Self Filler Tank

Capacity(litres)Operating Pressure (kPa)Element Rating (kW)Mass Empty (kg)Filler Tank Water Inlet Connection & Air Vent (BSP Male)Solar Tank Water Outlet Connections (BSP Male)Overflow Connection on End Dome (BSP Female)Width (mm)Diameter (mm)

Solar Vacuum Tubes

Tube Dimension A (mm)Dimension B (mm)Dimension B (mm)Dimension B (mm)

For more information and/or specifications, please refer to the Brochure

Installation & Warranty

Download Installation & Warranty Manual


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