after spending a little time finding the right sort of temp for the water i thought i would give it ago! got the water to about luke warm to start with, i had a first clean to do today so thought i would try it out on that, think they said it been a long time, the upvc frames was covered in that black dust and muck on the tops of all the frames. seemed great, moved the bird muck off with out any trouble and cleaned them well i think, it seemed to make it a quicker job. also on the plus side, if it always runs as it did today i wont need to worry about gloves, my valve on my pole and pipe was nice and warm. looking forward to using it a little more now when its all 100% finished.