Rectorseal68708 1.2-Pound Calci-Free Tankless Water Heater Flush

We spent $325 wasted money on a service call. The guy flushed it with vinegar which did nothing. With this product the water came out black. Now the heat is consistent. I think those people who say not to use it just want you to buy a new machine. Highly recommended. Too bad though it’s so expensive.

Background you can skip:We have run our Tankless Noritz N0751 since 2008. We initially had the plumber come by yearly to do a flush at an outrageous cost and they used vinegar. 6 years in the unit would not kick in a fast, water flow was down and sometimes wouldnt even kick in. Plumber diagnosis: we have hard water and these units simply wont last long in that environment. Buy a new one for 3000$ for a retro fit install.I booted them out. Installed - should have done it years ago- isolation valves and used flow aide based on online recommendations. Ran diluted flow aide for one hour and came down to find the flush water black. The machine ran like new. Conclusion: Flow Aide > Vinegar, i.e. Flow Aide is better at cleaning than vinegar.However, flow Aide has gotten expensive. Recently I cleaned with the last bit of Flow Aide and when it ran clean I decided to try RectorSeal right after to see if it would still help. Whaddaya know, after 45 minutes i came down to find the water BLACK again. So my view is: RectorSeal > Flow Aide > Vinegar.Pros:Cleans well in well water / hard water environment. Our Nortiz Tankless is turning 15 with no end in sight.Beats the alternatives in effectiveness... and in priceCons:None yet.

We use this every 6 months and have had no issues with our setuo in terms of pressure

We have instant hot water heater & it needs to be cleaned to prevent hard water build up. We borrowed from a fried & replaced it with this product

Does the job. No much more expensive than the 4 gal. of vinegar alternative.