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 same as the non pressure solar collector. Rather than using the water in the tank directly, as the non pressure does, this type uses a 45m~60m copper coil.

Heat exchanger inside the tank procides more than 1.5m of heat transfer area. When water flows through the coil it absorbs heat from the water insode the solar colloector tank. The solar collector tank is therefore a thermal store.