Imagination Solar

Simple, Affordable, Effective: Using the suns energy to heat water

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What are the advantages of the ISL drain back system?


The drain-back system, which is very common on the continent, has a number of advantages over the pressurized system, which is common in the UK. Assuming the unit is installed as per the installation guides, then:
  • At night, when there is no sun or in other very cold weather there is no water in the panel to freeze, so plain tap water can be used in the system.
  • No chemical antifreeze is required, so there is no maintenance to check and maintain antifreeze protection for the system.
  • In very hot weather with no water draw-off [e.g. whilst away on summer holidays] the system is protected from boiling by draining back the water when the cylinder exceeds 80 degrees centigrade.
  • If you choose a mains powered system, then in the event of a power failure the system always fails safe, with water draining back out of the panel, where it will neither freeze nor boil.
  • Drainback systems can be ‘switched off’ without harming them, so we can offer high limit shutdown at 80C or 65C, which make the system ideal for use with un-vented cylinders.
  • Plain tap water is a better heat transfer medium than antifreeze, so carries a greater density of heat from the panel into the hot water cylinder.