DIY Doctor UK DIY Forums

Hi, I have just bought a Vaillant 837 to install in a 3 floor Victorian property which has been best part gutted.The boiler was scrapped some time ago the radiators are 15yrs+ old and I'll be replacing those.However the pipe work has a thick deposit of soot (pure iron oxide) throughout . How can I flush this through without the heat thats needed to make the chemicals really do their job.I want those pipes spotless before boiler goes anywhere near them. Any advice / experiences more than welcome. Thanks.

best thing to do is fit ur new boiler along with a magna clean (filter) this will protect the new boiler from the sludge already in the system. U can then add a sludge removing chemical to ur system, which will break up the sludge, then hook up the powerflush machine, clear the system, then add an inhibitor. The filter can then be cleaned out periodically, and extra inhibitor added when needed in the future.

Thanks Cheesie, I looked at the Fernox TF1 earlier today at Cov Plumbing , clear body display unit, looked for all the World like an upturned pop bottle, but if it does the job and by all accounts it does it very well, who cares.I think they must use rare earth magnets in them which would explain the price tag.If you're ever scrapping a hard drive open it up and take the magnet out they're incredibly strong.Thanks again for your advice.

1) The only way to get results with a sludge remover on a cold system is to have it in the system for weeks, before the power flush. Could also double the dose.
2) You could use a strong acid, but it very risky and not recommended.
3) Some power flush machines have a heating element attachment, which could help you heat the water while you flush.