Understanding Back Boilers and Boiler Blowback: A Guide for Home Owners

A back boiler, dating back to the 1960s and 1970s, was a central heating and hot water system. These boilers were produced by the market leader, Baxi Bermuda, and were typically placed behind a fireplace. Operated by either a gas fire or solid fuel, back boilers heated a large water tank that then supplied hot water taps throughout the house.

Back boilers were once the predominant heating systems, until the trend shifted towards more efficient and cost-effective condensing combi boilers. Replacing a back boiler with a combi can yield up to 20% more heat for the same money. With the UK government offering grants of ￡100 to replace back boilers, these outdated systems are rapidly being phased out. However, around 5% of the UK population still rely on back boilers for their heating needs.

Boiler Blowback: Causes and Prevention

Boiler blowback, also known as burner backfire, is a hazardous phenomena that occurs during ignition. It happens when the fuel sprayed inside the boiler furnace ignites suddenly, causing a rapid expansion of combustible gases. This can result in the activation of safety devices, deformation of the boiler door, or even burner damage. The main causes of this issue include a fuel-rich mixture, the accumulation of unburnt gases from previous cycles, and restrictions in the flue gas path.

The Role of Hydrocarbons

Hydrocarbons accumulate inside the furnace as either vapors or liquids, waiting for the right conditions to ignite. When these vapors ignite, they generate high pressure inside the furnace, potentially leading to a dangerous explosion.

Preventive Measures

To prevent boiler blowback, it is crucial to follow these steps:

Sufficient Pre-purging: Allow enough time for pre-purging the furnace to remove any residual gases before ignition. Regular Maintenance: Carry out routine maintenance of the boiler burner and swirler according to the Planned Maintenance System. Periodic Inspection: Conduct regular inspections of the furnace to identify and address any potential issues.

Additional Resources for Home Owners

For more information and interesting topics, consider visiting our section on IQ NATURE.

This guide aims to help home owners understand the basics of back boilers and boiler blowback, providing practical advice on maintenance and safety. By following the guidelines outlined herein, you can ensure the continued safe and efficient operation of your heating system.