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SSU indirect descaling

SV9_9 Member Posts: 37
Hi, I have an SSU-45 indirect water heater that I want to descale / flush. It is 10 years old, and as far as I know it has never been cleaned. Would white vinegar be an effective solution for descaling? Would I get better results with one of the commercially available products, i.e. Flow Aide?
Thanks, J


  • Leon82
    Leon82 Member Posts: 684
    I've used both on my tankless.
    The vinegar is cheaper, but probably should run longer than a chemical. Mine I usually run over night with vinegar.
  • Ironman
    Ironman Member Posts: 7,377
    Shock the indirect: drain the potable water out, let the boiler run 180* water through the coil, and then fully open the cold water line to shock the hot coil. The scale will flake off and then you can flush it through the drain valve.

    This is what HTP recommends.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • SV9_9
    SV9_9 Member Posts: 37
    edited December 2017
    Thanks for the advice Leon82 / Ironman. I will let you know how much crud I remove. Thanks again, J