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Why SunTank

SunTank Solar Geysers

Established in 1994, SunTank is today South Africa’s leading and longest serving solar heating company.

  • When you buy a SunTank solar geyser system, you buy directly from the manufacturer.
  • SunTank solar geyser systems are 100% locally made by us in Pretoria and are specifically designed for the region’s challenging climate conditions.
  • SunTank is a leader in the implementation of Stainless-steel technology for solar heating.
    This ensure durability, longevity and best hygiene for the geyser.
  • SunTank’s solar geysers comply with SANS 1307 and are SABS high-pressure, 400kPa approved.
  • Installations in Gauteng are carried out by SunTank’s own trained technician.
  • SunTank solar geyser systems carry a 10-years Warranty and would last many years after.
Products - SunTank Solar Geysers

SunTank Installations

Options Types

Solar panels must always face North or alternatively NW/NE.
Installation of a SunTank solar geyser system can be configured in either:

Close-coupled – Tank and panels are mounted together on a single stand, where the tank is higher than the panels – on a pitch roof or a flat roof stand.

The heat transfer between the panels and the tank then takes place through a natural, thermosyphon circulation. Advantages of this installation option include:
⦁ Most reliable
⦁ Simple and easy to maintain
⦁ Least heat loss between the panels and the tank
⦁ Cheapest option to install

Split – When Close-coupled is not possible due to aesthetic preference or Estate regulations, the tank and the panels can be split, where the panels are outside on a pitch or flat roof stand, and the tank can be placed anywhere.

The heat circulation in a Split installation can be designed to be either thermosyphon or pump-driven.
For the thermosyphon pitch-roof option to be possible the height in the roof void should be high enough to lift and fix the tank so it is higher than the panels outside.

In other cases, in the pump-driven option, the tank can be installed inside or outside the house, horizontally or vertically. Advantages of this installation option include:
⦁ Better aesthetic
⦁ Versatility of places to conceal the tank
⦁ Option to choose the superior Vertical tank

Products - SunTank Solar Geysers

Close-coupled, Pitch roof, Natural, Thermosyphon heat-circulation Installation

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Close-coupled, Flat roof, Natural, Thermosyphon heat-circulation Installation

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Split, Pitch/ Flat roof, Natural, Thermosyphon heat-circulation Installation

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Split, Pitch/ Flat roof, Pump-driven, Forced, heat-circulation Installation

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SunTank FAQ’s

Frequently asked questions:

Why should you install solar water heating?

Heating water with solar energy from the sun is the most cost-effective technology in South Africa.

Save money – A SunTank solar geyser correctly sized can save you as much as 50% of your total monthly electricity bill and 80% of your water heating costs. The pay-back on your investment is less than 2 years, leaving thousands of Rands in your pocket, for many years thereafter.

Be independent – With a SunTank solar geyser you can still have hot water during load-shedding and power cuts. Electricity rates increase will have a minimal effect on your monthly hot water bill.

Go Green – Solar heating is clean energy, no pollution, no harmful impact on climate change and global warming.

How does a solar geyser work?

The SunTank geyser system comprises of a solar water tank and solar heat collector panels.

The glazed panel consists of a black copper absorption plate welded onto a copper pipe manifold. The manifold is placed in an aluminium insulated frame and covered with a 4mm, hail resistant tempered glass.

The sunlight energy goes through the glass and when it hits the absorption plate it converts into heat. This heats the fluid in the manifold pipes that then circulate to the tank. The circulation can be either natural, thermosyphon or forced with a pump.

In frost areas the fluid in the manifold is glycol antifreeze that circulate to the tank’s double-jacket heat exchanger. In non-frost area it is the water in the tank that circulate in the panel.

The circulation between the panels and the tank carry on right through the hours the sun is shining. At the end of the day, the hot water is stored in the insulated tank ready toward be used at bath time.

SunTank solar geyser are also equipped with an electrical heating element as a
back up, controlled by a thermostat that could automatically switch to top-up if the sun radiation was insufficient on a cloudy day.

How do I decide the size of my SunTank system?

A correctly sized solar geyser will maximise the benefit that can be derived by solar. You should choose the largest system you can afford or that your north-facing roof space allows. Existing electrical geysers of 150L shouldn’t be a used as a benchmark as they are repeatedly heated by (costly) electricity throughout the day.

In essence, the size of the solar storage tank should be big enough to provide your hot water requirements in a 24-hours cycle.

The number of people in your household and their hot water consumption habits determine the size of the SunTank system that you would need. A minimum of 50L per person per day should be the rule-of-thumb. A 300L SunTank is the most popular system in an average typical family house.

How hot does the solar geyser get and will I always have hot water, at night and in winter?

SunTank systems are designed to bring the water to around 50ºC -60ºC degrees in 6 hours of direct sun and to supply hot water 24/7, 365 days a year.

During the daytime, the geyser is heated by the sun and is stored in a B-rated insulated geyser that can retain the hot water overnight.

During cloudy conditions, SunTank’s standard electrical back up could be activated to ensure a constant supply of hot water.

Will a hailstorm or freezing damage the solar panels?

SunTank’s flat-plate collector panels are covered with a hail resistant tempered glass that is tested by SABS.

In frost area, SunTank recommends the Indirect solar geysers where the tank is made with a heat-exchange jacket and the panels are filled with antifreeze glycol heat-transferred fluid.

This is the only 100% safe technology to prevent frost damage to a solar geyser system.

What are the maintenance requirements of my SunTank system?

The maintenance of a SunTank system is minimal and should take place periodically. It includes restoring the heating performance in an Indirect system through the topping up of the anti-freeze fluid. In a Direct system, flushing potential dirt and sediment out of the panels should be carried out. At the same time when these performance restoring activities take place on the panels, the Sacrificial anodes in the tank are replaced.

(User Manual – download)

What is the lifespan expectancy and warranty of my SunTank system?

SunTank systems are made of the finest non-corrosive raw materials, stainless-steel, copper and aluminium. With regular maintenance they can last double the warranty period and beyond.

The SunTank system carries a 10-year warranty as a standard, terms and conditions apply.
(Warranty form -download)


SunTank User Manual 

How to makes the best use of your solar geyser

Dear SunTank customer,
Thank you for purchasing a SunTank Solar Geyser. With your SunTank you can now:

1) Save money on your monthly electrical bill

2) Have hot water regardless of the availability of grid electricity

3) Go green and protect the environment

To maximise the benefits from solar geyser investment, please read the following information:

  1. Maintenance of your Solar Geyser

To keep your solar system performing optimally, to increase its lifespan and to extend the SunTank Warranty, it is recommended to service the system routinely every 1-2 years.

The Routine Service on the tank and the panels includes: 

  • General visual inspection and fault-finding
  • Top-up of the antifreeze heat-transfer fluid (glycol) – in ‘Indirect’ systems
  • Replacement of the protective sacrificial anodes in the tank
  • Inspection of electrical components – element, thermostat, pump & controller (if included)
  • Inspection of the state of roof waterproofing – and maintenance if necessary
  • Confirmation of the soundness of the mounting structures – and maintenance if necessary
  • Cleaning and re-certifying the installation
  1. Management of the Electrical Backup – to optimise your Savings

Maintenance will keep your solar heating performing with no intervention required by you.

In addition to the solar panels, your SunTank geyser is also equipped with an electrical back-up heating element (same as in a conventional electrical geyser).

Obviously, to save the most, the electrical back-up element should be switched on as little as possible, while at the same time you should have enough hot water when needed. How much this electric heating element would be required to switch on depends on the weather and on the hot water consumption habits of your own household.

The electric element back-up might be needed:

  • When there is insufficient solar energy due to cloudy conditions
  • When the hot water consumption of the household exceeds the storage volume capacity of the geyser.

The electrical element can be managed in 2 ways: 

  1. Manual management of the geyser’s DB Trip-switch

To manually control the electrical back up it is beneficial for you to keep the geyser’s trip-switch in the DB board at the OFF position as much as possible. Only switch in ON manually after sunset only when you suspect that the sun wasn’t shining enough that day due to heavily overcast conditions.

You will learn trough experience how long you need to keep the electrical backup on to meet your specific household’s hot water requirements. 1-2 hours should typically be enough. Then, switch OFF the trip-switch before you go to sleep to avoid the geyser reheating all through the night with electricity. The geyser will stay hot overnight and the solar will start its heating cycle at sunrise again.

  1. Automated management with a Geyser Timer or a Timer-controller unit

 To automate the electrical heating back-up, you can have a Geyser Timer installed by an electrician in your DB Board or have a Timer-controller unit linked to your SunTank. (The latter is included as standard with a pump-driven installation).

Set the ON time in the Timer for approximately 1-2 before your bath time, preferably outside of the effective hours when the sun is still shining. When the timer reaches that ON setting, the thermostat will then detect if the back-up heating element is necessary or if the solar heated the water enough.

Each household’s hot water usage and requirements may differ, but the principle of the electrical back-up is similar. To maximise the savings out of your solar heating, have the longer ON timer session in the afternoon when geyser is at its hottest so the thermostat will prevent unnecessary electrical heating in most days. Set the ON morning period to a minimum to ensure just enough re-heating for the last person using hot water. If no hot water is used the night before, try to skip the morning ON settings altogether.

Here is a diagram as a reference for the Timer setting where most people bath in the evening and few in the morning:















Bath time





Timer ‘ON’




Remember that the Geyser Timer is not an integral part of a solar geyser system. Any qualified electrician can install it after your SunTank solar geyser was installed. Once installed, always keep the geyser’s trip-switch ON at the DB-board.

Alternatively, an electrician or SunTank can install a Timer-controller linked to your solar geyser installation. Not to worry, in a pump-driven installation where the Timer-controller is included, changing the electrical back-up times will not disrupt the pre-set pump control function. Familiarise yourself with the manual of the Timer-controller brand you have, of the various operational settings of the element timer and thermostat control functions.

Remind yourself to book your Routine Service, every 2-years for a thermosyphon system and every 1-year for a pump-driven system.
Then book your service on the SunTank website or contact us on

Thank you once again for choosing SunTank and enjoy the benefits of South Africa’s top solar geyser system for many years to come.


Warranty form – download

User Manual – download


Get a Quote for your House

SunTank offers installation services for homeowners in Gauteng. Our recommendation is to ‘go big’ so to enjoy the most benefits of a solar geyser. SunTank’s own technicians install solar geysers systems in 200L, 300L and 400L only. We suggest suburbia homes to have a 300L solar system or bigger if budget and roof space allow.

For collection, we also offer 100L and 150L solar geysers systems.