Why should I get the water in my central heating system cleaned?

If sludge is allowed to build up, it can result in blocked pipes, inefficient radiators and damaged parts in the boiler.


The heat exchanger in a boiler consists of many narrow pipes which the water passes through to heat up.  If the narrow pipes become restricted or blocked, the boiler will shut down to prevent it from overheating and getting even more damaged.  If the boiler breaks down because of sludge in the system, the repair work is not covered by the boiler warranty and could lead to expensive repair bills.


Sludge can cause:


  • Damage to the boiler
  • Damage to the boiler pump
  • Damage to radiators, including leaks
  • Damage to radiator valves
  • Blocked pipework, including on the heat exchanger
  • Higher energy bills

What is central heating sludge?

Sludge, or magnetite, to give it its proper name, is a black substance in the central heating pipes made up of dissolved and rusted metal.

How do I know if I've got sludge in my central heating system?

Read on to find out what the common signs of sludge in your central heating system are.