Finned Tube Type Heating Boilers : NS Labour and Advanced Education, Fuel Safety

Fuel Safety Bulletin 2002-02b

Regular inspection and maintenance of finned tube heating boilers is extremely important. The fins in the combustion chamber in this type of a boiler are susceptible to condensation. A chemical reaction involving the condensed products of combustion causes oxides to form on the fin surfaces. If left unchecked, these oxides accumulate and eventually restrict the flow of combustion products through the fins. Regular inspection and maintenance of the boiler should be conducted during the period that the boiler is in operation.

For a proper inspection, the flue pipe connected to the boiler must be removed.

If deposits are found, the finned tube section must then be removed from the boiler casing, and submerged in a chemical bath or cleaned with other equally effective means.

If the deposits are not removed, it may affect the appliances venting, resulting in carbon monoxide being produced and spilling into the building.

The deposits which build up on the finned section are combustible, and extreme caution must be taken to ensure that the deposits are not ignited or caused to explode by attempting to remove them with a wire brush or a metal object such as a screwdriver.

The formation of oxides occurs more rapidly if the return water temperature is too low or if there is too great a temperature differential between the supply and the return. Consult the manufacturer's instructions for exact minimum temperatures for each individual boiler. In multi purpose applications, the system may have to incorporate mixing valves or a heat exchanger to maintain system temperatures and proper return temperatures.

When installing or servicing these appliances, installers should always advise the owner of the importance of regular maintenance and servicing of these units.