Central heating inhibitor is a maintenance measure for your boiler.
You add a chemical solution to the water to keep it working efficiently, prevent malfunctioning, and to extend its life.
In particular, with metal piping and components, rust, limescale, and dirt can build up over time and may cause blockages and affect the performance of your boiler. This can also increase energy costs if your boiler starts to operate at sub-optimal efficiency.
With a combi boiler, it is important to add the central heating inhibitor to the system after it has been cleaned or received its maintenance check – usually annually at least.
Make sure the heating is turned off and the radiators are cool. Add the inhibitor directly into one of the radiators via the bleed valve or (in the case of towel radiator) via the plug at the top.