Okay, so when you open up a boiler and find this much sludge present in the heart of it’s workings then one can feel a little disappointed. Why didn’t the owner get a filter installed to help protect the system? A new boiler and power flush is going to cost thousands of pounds but an magnaclean filter is going to cost you £200 inc the parts and installation. The maths speaks for itself. Ho hum, I guess if you have a short term budget you have a short term budget but if you have a few more quid.. Get a filter installed!