power flush

I don't think it's a regulation, in the sense of a legal requirement, but manufacturers usually reccommend it, and failure to do so may invalidate the warranty.

Have a look at this site - they make the equipment, which you can rent out and explaing the process pretty well. I've never done it, but supposedly the machine does all the work for you. Your challenge is draining the system, connecting the machine to it effectively, and then refilling the system when it's all done.

I don't think I have ever seen a plumber do a power flush when changing a boiler. And that is hundreds of boilers.

They do however do a non power flush with chemicals. Usually after the boiler is installed if new rads are fitted and sometimes before the boiler is swapped if the radiators are staying.

There certainly was no ned to powerflush my brother CH when he had his boiler swapped. The inhibitor we fitted had keep the water clean.

Adam