The thermal efficiency of boilers depends upon how effective the heat exchanger is in absorbing heat from the combustion gases. The combustion of kerosene produces acidic gases which attack the heat exchanger forming an oxide layer on the surface whilst also depositing solid particles of sulphur and soot especially on cooler areas.
The build-up of deposits on the heat exchanger inhibits heat transfer into the central heating and domestic hot water systems and lowers the thermal efficiency of boilers between services. This impacts upon the temperature and composition of gases exiting the boiler flue and results in a lowering of combustion efficiency as measured by flue gas analysers.
Heating oil additive products can contain a mixture of anti-oxidants, detergents, dispersants, corrosion inhibitor, metal deactivator and other stabilisers. They work in combination to reduce deposits and provide total system protection right from the moment the fuel is first put into the storage tank right through to after the fuel is burnt.
They work by cleaning up dirty boilers, fuel system and storage tanks; keeping “existing clean” systems clean and protecting them, plus avoiding problems that regularly occur with boilers that the customer does not always know are happening (because the boiler still runs).
Clearly, boiler energy efficiencies are directly influenced by combustion efficiencies and any change in the latter will be mirrored by a change in boiler energy efficiency. Combustion efficiency is routinely set at the optimum during the annual boiler service by an engineer.
However, any change in boiler performance (away from the optimum) which might occur between services could well lower the combustion efficiency. For example, any deterioration in fuel quality could reduce the energy generated on combustion. Additionally, contamination of the heat exchanger with soot could lower the rate of heat-transfer into the circulating boiler water.
