this is not wishing to wind up anyone, but it must be a record! This is in my house where I live.
I moved here in 1975! that is over 37 years ago! There was no Central heating but only gas fires in every room!
In 1976, I had CH installed on the ground floor only with 5 double rads.
Ironically the heat rises so upstairs was not too cold, and never felt the need to take CH to first floor, right till now except one bedroom where I sleep!
For the record, we have only ever had 2 boilers installed so far.
The first boiler was Vaillant VCW sine 18, it served me very well until 1994, that is 16 good years! Then when I had my extension build at the rear, 3 more rads went in, and the sine 18 was then replaced only because it looked old, it had nothing wrong with it, during its life I remember replacing just the diverter valve wax module, and nothing else. it was never serviced and only repaired when minor faults developed as stated above.
The pipe work was never flushed, or filled with any additives or inhibitors! in 1976 CH was relatively new, and there weren't many houses with CH or even Double Galzing that time.
Then as the new extension was build, the old sine looked old, not fitting with modern style, it was too long a boiler, so I decided to upgrade with VCW GB221, that is now 20 years old, and still running trouble free, in its 18 years life, it had its lower heat exchanger skirt replaced, servo valve replaced, differential valve that pops a pin up when you open hot water tap - that was replaced, and the main diverter valve diaphram replaced,
and the DHW plastic HX was replaced with a plated HX about 10 yaers ago, just these few parts! The top primary main heat excahnger is still original, the original pump is still ticking along happily!
Again it was only ever serviced properly whehn its lower heat exchanger skirt went, it is made of a sheet of copper and surrounds the burner.
When this boiler was installed, the pipe work was not flushed, no chemicals or additives were added, and about 2 years ago it started to loose water pressure, the cause was an internally leaky expansion chamber! so without having to take the boiler off the wall, I added an additional expansion vessel that I bought from a scrap boiler merchant for 20 quid! and since last year not a drop of water has been added to the system. No lies what so ever!
That is for the record, so if I got myself a new boiler installed by anyone, I would refuse to buy into adding chemicals, rust inhibitors, and so on, 37 years on, not a single leak on my pipework, or on any radiators, so this is why I find it hard to accept that you must need all this BS power flush and inhibitors, you have to convince me some other way!
what I think must happen is when installers use too much acidic flux, and that is what may be causing these problems, corrosion etc, none of my rads has ever been blocked, or required to be removed to remove any sludge, i am not saying that it hasn't got any sludge, it must have some, but so far in 37 years it has not caused me any problems, this must be a record, and if you like my boiler is probably fit to serve for another 5 or may be even 10 years provided I keep the pro away from it.
sorry but I don't easily buy into things, door to door salesmen come offering me free loft insulation......free..my foot, is there such a thing as free, I just send them packing!
Please don't react adversely, if you don't believe, then! come and have a look for your self!
On top of that, I could show anyone, who challenges me, another installation where the pipe work has never been flushed not even after completing the pipe work, or additives added, Biasi S24 runs like new and never packed up even once except when a mice got into the circuit board some how, and did a piddle on its spark generator and HT tracks were wet, that is when it wouldn't fire up, cleaned that piddle and it was good as new! and that installation is still running like new, not topped up more than once or twice in its 10 years since installed! that is another record!
I think it is the same thing as companies trying to sell their products even if they don't really do sod all, Do you take Multivitamins? why not?