Powerflushing a system with a Powermax

[Zippymark]

Hello, I have a job with a Potterton Powermax system that is badly clogged up with sludge/rust from several leaks/ignored problems etc.

I want to powerlush it to try and solve some of the problems, and I just want to get clear in my head how to go about this.

I guess i'll disconnect the heating flow and return, and do the actual heating system first, then do the powermax afterwards, so i guess my question is- is where the heating flow and return comes out of the Powermax unit just like a connection to a cylinder, or is there a coil involved there? So if i then connect my machine there it'll be cleaning out the 'cylinder'?

Is this the best way of going about it do you think, or is there a better approach?

Thanks in advance for any help.