Combi boilers are easily the most popular boiler type, thus, they are economical to run and can produce an endless supply of hot water.
Combi boilers are typically compact; they can be hung conveniently on a kitchen wall and their installation is less disruptive and less expensive than that of conventional boilers.
The way they achieve their high level of efficiency is through removing the energy from the fuel it is burning and also reducing the temperature of the flue gases into the point where water vapor produced becomes liquid that then releases heat that otherwise in Combi Boilers would be lost up the flue. Combi boilers generate water on demand for your taps and central heating from within the boiler unit.
A combination boiler combines the functions of a central heating boiler and an instantaneous multi point water heater, giving priority to the supply of domestic hot water. Combination boilers can be direct or indirect in much the same way as the cylinders above, using calorifiers (heat producers) to heat water passing through them.
Combi boilers heat water instantaneously whenever you turn on a hot tap. So there's an endless supply no matter how much you draw. Because you don't need a cylinder to store hot water it means you save on precious space.
One small disadvantage with a combi boiler is that although a continuous flow of hot water is constantly available, the water flow rate from combi boilers is not likely to be as good as with a traditional storage cylinder, particularly in winter. Combi boilers do not require this hot water storage saving you valuable space and reducing heat loss from the previously stored water. Not as good for multi-bathroom properties. Requires good water pressure.
Benefits - No tank or cylinder required- Minimal pipe work- Quick and easy installation- Mains pressure domestic hot water- Ideal for showers- Ideal for flats
Example of Combi Boilers: 1.Drain cock 1. Drain cock 2.Incoming cold feed 2. Incoming cold feed 3.Main tank immersion ( night use mostly) 3. Return to boiler 4.Top up immersion 4. Flow from boiler 5.Vent pipe leading back to cold water tank 5. Heat exchanger 6.Hot pipe to feed taps. 6. Immersion 7.Cold feed out. 7. Hot feed to taps 8.Hot from boiler 8. Vent pipe.