This type of solar water heater provides mains pressure pre-heating via a highly effective copper coil heat exchanger located within the solar collector tank. The way in which the mains pressure solar collector heats water is the e as the non pressure solar collector. Rather than using the water in the tank directly, as the non pressure does, this type uses a 45 - 60 m copper coil.
Heat exchanger inside the tank which provides more than 1.5m 2 of heat transfer area. When water flows though the coil it absorbs heat from the water inside the solar collector tank. The solar collector tank is therefore a thermal store.