what is the cost of de sludging central heating system?

Before deciding use the search box on the top right of this page with the three words:

british gas flush

and read some of the answers - B Gas have a habit of upselling and often offer the customer a power flush - sometimes as a condition of offering a guarantee for the original work done.

Peccavi
April 2009

That is indeed the cost, or thereabouts, for a powerflush unfortunately....it depends on the degree of sludging, naturally. Its possible to do it yourself to a degree, but this means disconnecting and draining the radiators, flushing them with a hose pipe, and then allowing fresh water to flush out the pipe work. Not something you should undertake lightly by yourself! If you bleed the radiators, and the water that comes out is black, it shows that there is sludge present. The sludge also produces its own gas, which means that the radiators need bleeding quite frequently.

John
April 2009