How do you flush out a central heating system?

[Quiet Man]

How do you flush out a central heating system? Do you use a chemical compound or what? I have just replaced my radiators with high output ones and replaced the boiler so should I try and flush the remaining pipes before filling? Any advice would be great, thanks.

[Hard@it]

You have obviously just emptied the system and probably not for the first time ! Fill the system and check for leaks, if all ok then get a liquid inhibitor. Empty a radiator, then pour it in to it and once you run the system the pump will circulate it. Cheers Hard@it.

[Catso]

Yes, you can get chemicals which are supposed to help clear out the system. B&Q, Wickes & such like sell them. Buy a good make. If you are in the middle of messing about, I would say it is worth doing.

You fill the system, add the stuff, run it for a few days, then empty and refill with clean water (& your inhibitor). It works best if you run the system hot, for a few days, so perhaps now isn't the time to do it! Wait till it's a bit colder.

[Hard@it]

Sorry, meant to say that unless you have a problem there is no need to dose and flush your system just because you have replaced some rads. Also that the inhibitor is there to protect your system so do not empty it out leave it in permanently.

[Disco Fever]

If youve fitted new rads and a new boiler then I would fill the system with water to check for leaks then empty the system again to get rid of any old water and rust you get from old systems then get some good chemicals from B&Q or any Plumb Centre but Catso has the best idea.