Cleaning a combi heat exchanger

[Keith D]

Some time ago I posted a question on how to clean a combi heat exchanger. I resolved the issue with remarkable ease using powered citric acid at 20% solution in water at 85 c. Cleaned it in about 40 minutes. I was so impressed that I removed and cleaned all my right angle compression joints!!!

[bof]

In message , Keith D writes

I'm pleased to hear this as I need to descale the hot water heat exchanger in mine, how did you circulate the solution? How could you tell when it was done?