Radiators can make a lot of noise, and one of the most common sounds you might hear is a clanking noise. This can be caused by a number of different factors, and understanding the cause of the noise is the first step in fixing it.

One of the most common causes of clanking radiators is air in the system. When air gets trapped in the radiator, it can create a clanking noise as the water runs through the system. This can be caused by an improperly bled radiator. To fix this problem, you will need to bleed the air out of the system.  Some systems have automatic vents or air eliminators, it is also a good idea to inspect and service these as well.

Another cause of clanking, banging radiators is thermal expansion, this occurs in two ways.  The first and most common is rad stretch, when the boiler turns on and the radiator begins to heat the iron expands and the radiator lengthens, the friction of the rad legs on the floor will often bang as the rad gets longer and again on cool down when the rad gets shorter.  The second noise that is a result of expansion is when the pipe feeding the radiator lengthens from thermal expansion.  These pipes often run through floor joist and flooring and as the grow the make noise, in addition to a bang another common sound is that of a marble being dropped on the floor, tick tick tick tick progressively quieter and closer together.

Finally the noisiest rads of them all, STEAM!!! Steam rads can have a multitude of circumstances that can cause banging, it is usually the result of hot steam contacting cold water in the piping of the rad.  Because water multiplies its volume 1600 times when it becomes steam, when this happens inside a confined space like a pipe or radiator the rapid expansion of the water will sound like an orchestra of tiny steam fitters beating your pipes with a hammer.  Ensuring valves, steam traps, radiator air vents are all in good working order can significantly reduce these issues, as well as the pitch of the rad so condensate can effectively leave the rad.

In conclusion, clanking radiators can be caused by a number of different factors, including air in the system, To fix the problem, it’s important to have a professional first identify the cause and then take the appropriate action.