Hi I need help on a power flushing job, the f&E tank was very dirty and had about 6 inches in sludge. I removed tank cleaned outside and refitted. I then purged the system refilled then closed all downstairs rads then added 800x to flusher and got it into all rads upstairs but 1. As they all went warmish closed off all other rads and started to flushing 1 rad at a time leaving them closed as I went excluding the 1 that would not clear. It took about 6 hours, was very dirty but got them all hot. Repeated this again downstairs which most were quick to do maybe 3 and bit hours but got them all hot and clear. When I took off the power flusher and set the system back to normal nothing upstairs worked worth talking about. 2 rads downstairs very slow and the rest were hot. In total this took 12 hours and house is 2 storey, 1 oil burner, 17 rads 2 cylinders 2 back boilers 2 open fires which I cant acess the pumps to these. Customer doesn't want to ruin decor, is it a must to get onto these pumps or will the power flusher reach the back boilers from the circulation pump on oil burner using a kamco cf 40? I am going back tomorrow to add more cleaner, any advice on cleaner type that I can leave in for a week or so to give me time to help decide what to do next with this job? HELP PLEASE, THANKS