Unvented Hot Water Cylinder
- 9-
If a motorised valve is used this must be fitted on the primary return due to possible high temperatures of
the solar circuit.
3.5
Solar Heating system
The solar heating system is a closed hydraulic system in which the heat transfer fluid transfers the
heat to the water in the cylinder via a heat exchanger.
The water in the cylinder is heated by two separate circuits. In the lower coil the water is heated by
the solar circuit and as the water in the lower section of the cylinder is generally at a lower
temperature in enables sufficient heat transfer even when the solar radiation level is low. The
upper coil is heated by an external heat source (boiler or immersion heater) and heats the upper
section of the cylinder from which hot water is drawn for domestic purposes.
3.6
Cylinder control components
