Hi, we was getting lukewarm water from mates heatline vizo 24. I found a topic on this site which had same problem and they were advised to remove heat exchanger, flush it through etc, so i tried the same, removed exchanger, flushed it through, got lots of little black bits come out of it. Descaled it in solution for about an hour and the exchanger looked nice and clean. Put it back together and it worked fine for 2 days, we were getting hot water on a decent flow. But now we get lukewarm water, then cold, then lukewarm again. Can anyone advise on what may be the issue now and how to rectify this? Could the heat exchanger be blocked again, only after a couple of days?
