Have you had a new boiler installed? Or a complete new system? Then you need to have your system flushed.
The sludge from your old radiators can soon attack or even damage the working of your new boiler, shortening its working life dramatically.
"But I'va had a complete new system installed why do I need a power flush?"
The flux used by the installer will be floating round and "eating" your system from within.
In either case the flushing machine cleans out all the unwanted baddies in the system and the chemicals used help neutralise the system to stop it corroding.
What usually happens in a power flush?
Well in the case of an old system a pre-treatment chemical is added sometime before the flush is done. This helps break up the sludge so it can move freely around the system.
Then when the machine is being used it helps churn out this sludge and dump it outside. A second stronger chemical is used while the system is on to give it that "deep clean". This is also flushed out thoroughly as it is so strong if left in too long can also eat the system
Once that chemical is flushed a reading is taken from the water in the system it is measured against the water from the incoming main supply.
When in tolerance the final chemical solution is added, this neutralises the system to stop it corroding further.