Is there a "typical" interval for doing a powerflush? Reason for asking is that it was mentioned on a recent visit by "ServeHome". I couldn't swear to it, but I'm sure that when it was done previously I was told that I only needed it to be done once. History: All in 2009. New Boiler (British/Scottish Gas 330+ High Efficiency Boiler). Installed MagnaClean Filter. PowerFlush done. Installed System Water treatment. Boiler serviced - Annually (2009-present) So coming up to 10 years since the install above. Is this typical time-span after which efficiency falls enough to require further action e.g. Boiler replacement, power-flush etc ? Is it something I can check myself e.g. If the radiators aren't warming up enough, or there are cold spots in them etc . then is that a sign of accumulating sludge ?. Can't say I have noticed anything obvious. I do get situations where they are hot at the bottom and cold at the top. But usually I just use the 'key' to let the air out from the top and then they seem to fill up ok. Probably "how long is a piece of string" question, but just wondered if anyone had any thoughts. Many Thanks.