You can perform a simple test to check whether your home radiators are filled with hydrogen, using only a cup, a radiator valve key and a match.
Just get ready to open the radiator valves using the bleed key, and place the cup upside down at the head of the bleed valve, opening it gradually until a hissing sound emerges as gas is released.
Then, close the valve quickly and light the match beneath the cup.
If a small popping noise results, it indicates that gas has been ignited, suggesting your radiators are filled with hydrogen and not just air. For a more detailed insight into radiators filling with air or hydrogen and how to tackle the issue, browse our dedicated blog, Why do my radiators keep filling with air?