Oil Fired Combi Boiler

A combi boiler is similar to a conventional boiler with a second heating circuit which instantaneously produces hot water.

Second heating circuit

Often overlooked is the fact that the operating / engineering differences between gas and oil fired combi boilers is significantly different.

Oil fired combi’s, unlike gas, do not have modulating burners to cope with additional heating demand when a hot tap is opened.


This problem is addressed in two ways:

      - an integral water store making them physically big.

      - a larger boiler output than is actually required to satisfy central
        heating demand; you might end up with a 30kW boiler where
        a 20kW conventional boiler would suffice and also be more


When the heat store is exhausted, hot water flow of 10-13ltrs / minute @ 35oC rise above mains temperature is around the norm. To fill a bath (112ltrs) will take about ten minutes, provided no other taps are opened.


High life-time costs... unlike a gas combi, water is stored in the boiler at circa 80oC,  components subjected to this constant residual temperature will fail. Oil fired combi boilers are complex, have bespoke components; they will be more expensive to maintain than a conventional system. Good business for boiler manufacturers, not necessarily the best option for the homeowner!


So what's the solution? - Keep it simple! In so many cases a conventional boiler with a pressurised domestic hot water cylinder such as a Megaflow is a far better option.


The benefits:

        - loads of hot water at mains pressure - up to 72 litres per minute

        - back up immersion heater

        - industry standard components



Combination Boiler  


For more information on our oil fired combi boilers, to find an installer near you or for spare parts visit our contact page, or call us on 0845 680 8153.