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What's the preferred product to descale a tankless water heater?

pvs2487 Member Posts: 7

I've got a Jacuzzi branded Riniai tankless water heater that's due for maintenece/descaling.

It has the isolation valves installed, so it looks pretty straight forward. The manual states to use a couple gallons of vinegar as the flushing solution, but I've seen products (like Haymaker) available that have good reviews.

Any preferences from the experts?

Thanks in advance.

Peter Van Syckle

Cape May, NJ


  • SuperTech
    SuperTech Member Posts: 2,205

    I use white vinegar or a product called Flow Aid. For really badly plugged copper coils Hercules Sizzle can used.

  • GGross
    GGross Member Posts: 1,105

    I use the Haymaker descaler on mine, plenty of people run vinegar and are happy with the results. Make sure you let the pump circulate the descaler for a good long time. I think Haymaker recommends 30-45 minutes, I usually let it run about an hour. Make sure you flush out the heat exchanger with fresh water after using any product to descale, clean any filters that may be in line before and after flushing.

  • hot_rod
    hot_rod Member Posts: 22,476

    do you have a pump?

    The Haymaker kit comes with the pump, container and product. I think it works faster than vinegar and a different smell🥴

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • pvs2487
    pvs2487 Member Posts: 7

    Thanks for the advice!


  • jumper
    jumper Member Posts: 2,331

    I remember muriatic acid whatever that is. Not supposed to go down drain.

  • ethicalpaul
    ethicalpaul Member Posts: 5,795

    It's a friendlier name for diluted hydrochloric acid. If the manufacturer says vinegar, that's a pretty cheap thing to try first

    NJ Steam Homeowner.
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