How solar heating works

Text? The coldest water at the bottom of the hot water cylinder is pumped up to the solar panel where it is heated by the sun and returned to the cylinder, and by this means gradually heats up all the water in the cylinder.

It is standard practice to leave the backup heating source (electric element, gas, oil etc) switched on so there is still sufficient hot water when there is bad weather, or if there has been a larger than normal draw off of hot water.

Many people find it is possible to leave the element turned off over summer. In winter when solar levels are lower, the element may be turned on to boost cylinder temperature.

When should the solar pump turn on?

a. Retrofit, or new system using standard low pressure, glass lined or stainless steel hot water cylinder

With the standard configuration your system is fully automated, and the pump will turn on under the following conditions:

When the water inside the solar collectors (panels) is sufficiently hotter than the water in the bottom of the hot water cylinder, the   pump will turn on and transfer this hot water to the cylinder.

As cold water circulating from the bottom of the cylinder cools the panel down, the pump shuts off until the water is heated again. This process is continually repeated as the water in the cylinder gradually gets hotter.

When the water in your hot water cylinder reaches the (adjustable) target temperature the pump automatically shuts down, protecting   the hot water cylinder.

If you are in an area that experiences mild frosts in winter, the pump will turn on if the water in the panel approaches freezing point.   The pump will take a small amount of cold water from the bottom of the cylinder and transfer it to the panel to prevent the water in      the panel freezing, thereby protecting the panel from bursting. Once the temperature of the panels rises above the critical danger   point the pump will shut down, again minimising heat loss.

b. Retrofit, or new system using heat exchanger and anti freeze

With the standard configuration your system is fully automated and the pump will turn on under the following conditions:

When the anti freeze mixture inside the solar collectors (panels) is sufficiently hotter than the water in the bottom of the hot water   cylinder, the pump will turn on and transfer this heat to the cylinder by means of a heat exchanger.

As cold water circulating from the bottom of the cylinder cools the panel down via the heat exchanger the pump shuts off until the panel gets hot again, and this process is continually repeated as the water in the cylinder gradually gets hotter.

When the water in your hot water cylinder reaches the (adjustable) target temperature the pump automatically shuts down protecting   the hot water cylinder.

Even if you are in an area that experiences severe frosts in winter, the system is protected from freezing, as the solar panels are   filled with anti freeze (food grade).

The anti freeze does not mix with the house water because it is sealed in a different circuit, and transfers its heat to the house water through a heat exchanger. Just like in a car radiator the panels are protected from freezing by the anti freeze.

c. SUNZ or Rotex drain down systems

With the standard configuration your system is fully automated and the pump will turn on under the following conditions:

When the temperature inside the solar collectors (panels) is sufficiently hotter than the water in the bottom of the hot water cylinder,   the pump will turn on and transfer this hot water to the cylinder.

As cold water circulating from the bottom of the cylinder cools the panel down the pump shuts off until the panel is heated again, and this process is continually repeated as the water in the cylinder gradually gets hotter.

When the water in your hot water cylinder reaches the (adjustable) target temperature the pump automatically shuts down, and the   water drains back down from the solar panels preventing any overheating problems.

When the system stops producing heat the pump stops automatically, and the water drains back down from the solar panels   preventing any freezing problems...

no water, no freezing, even in severe frost areas.