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Yellow Flame or Popping Noise? Your Aga Range Cooker may be Suffering from Low Sulphur Fuel (LSF)

If you notice a yellow flame or popping noise coming from your Aga range cooker (or other oil range cooker for that matter!), you may be suffering the effects of Low Sulphur Fuel (LSF).


If running correctly, an oil range cooker should have a pretty blue flame, with telltale signs that LSF is being used being: 

  • Yellow flame
  • Range cooker struggles to reach maximum temperature
  • ‘Popping’ or ‘spitting’ noises
  • Strong smell of oil/fuel near the cooker
  • Black or red-coloured carbon deposits inside the cooker itself 

These symptoms can often progress from ‘mild’ to ‘severe’, and may ultimately result in the range cooker extinguishing completely as the fuel pipe becomes blocked due to fuel not burning off correctly. This buildup of carbon means you will need to have the cooker serviced prematurely. 

It’s also important to note that these issues can appear even if using the same fuel from a supplier which has previously caused you no issues.

What is Low Sulphur Fuel and what is the Solution? 

Low Sulphur fuel was a measure brought in by the EU to prevent air pollution, and most range cookers will not suffer any issues running on this. 

It’s important to note that before you conclude that LSF is the problem, you want to consider if there any other fuel-related issues that could be causing the issue, such as: 

  • ‘Overfueling’- usually after a service, too much oil can arrive at the burner base causing excess soot. The oil control valves will need to be adjusted by the engineer to rectify this.
  • Similarly if the burner base has been re-installed lower will mean the oil doesn’t burn correctly, resulting in a yellow flame and more soot!
  • A change to the flue may mean it draws too much or little air from the cooker causing either temperature issues or ‘sooting up’. 
  • If using an Aga range cooker, also double check the type of fuel - it will require 28 second commercial kerosene oil. This can also be know as 'class 2 kerosene to BS 2869 standard' - no cheap alternatives! 

If you have exhausted all other options, you may need to supplement your fuel with an additive to get it burning correctly. Ask your engineer for their recommendation on this, but that should solve the yellow flame and other problems often caused by LSF.


Blake and Bull are friendly Aga range cooker specialists. We offer handy accessories such as hob covers and spares

We also provide services such as electric conversions and fully reconditioned cookers made to order.