Gas Boiler Schematics
A combi boiler comes complete with a built in heat exchanger for providing domestic hot water on demand. When a tap or shower is turned on, the cold water is drawn through the boiler and instantaneously heated.
Storage Combi Boiler
A storage combi boiler comes complete with a built in storage tank (generally 45-60 litres) for providing domestic hot water on demand. When a tap or shower is turned on, the cold water is drawn from the in-built storage tank.
A system boiler has no built in storage or heat exchanger. As a result, it must have a separate water heating tank. It heats the domestic water indirectly through a coil in the water heater.
System Boiler with Solar
It is very easy to combine a system boiler with a solar heating system. This is done by installing a twin coil water heater and connecting the boiler to the top coil and the solar to the bottom coil.