1200psi I run 140°F water through the line first and continuously while flushing but the pressure washer is cold, once I have the hose all the way in then I turn everything off and feed a gallon of liquid plumber in and wait 30 minutes turn the hot water back on and let it run a few minutes and then pressure wash coming back out to the clean out and forward again a few times. This has worked well in the past and I had a free flowing drain for a couple of years. The pressure hose is moving easily without resistance until I hit the stop. It sure did not work this time?