Hi Phil, understand it's your choice to PF every boiler change, all be it not a requirement, but you must make an additional charge on each job to cover extra time, and any maintenance costs on the PF unit, But you must have come across systems that it is not possible to PF, I like you own my own unit and have done so for over 10 years, But I don't think its necessary to PF every job, but that's my choice based on the condition of the system, & meny years experience in the trade ! I find that in this area (soft Water) using a good quality cleaner with filter works just as well, PF-ing does not guarantee to remove everything in the system, With your commitment and insistence on PF-ing are you by any chance ex BG ? What Hammers is saying, if he deems it necessary to PF something then he will hire a unit,