Rectorseal68708 1.2-Pound Calci-Free Tankless Water Heater Flush

Mix 2 gallons of water with it in a 2 gallon bucket and circulate it in your water heater following the instructions. It says to use for 20 minutes, but it'd been a while since I kept up with the routine maintenance so I ran it for 2 hours. You should've seen the water after. Definitely cleaned a lot from the tank. I'd hate to see what the pipes in my wall accumulate

I was unaware that on demand water heaters needed to be flushed out from time to time, until my first one died (after a dozen years or so) and the service guy said "When was the last time you flushed this one out?" He seemed surprised that it lasted 12 years with no maintenance. They are not inexpensive to replace, so decided a bit of an investment in maintenance might prolong its life.And with products such as this, it is easy to do. You can get a kit, or make your own. A sump pump, two longish washing machine hoses, and a bucket. When yours was installed it should have two hose connectors on the bottom. Close off the water in and out, take off the caps, attach the hoses, turn on those valves to the heater from the bypass (sump pump out goes to cold in, and the hose back to the bucket is hot out, but probably does not matter if you do it backwards). This product you mix with a gallon of water in the bucket. I understand that vinegar does the same thing, but I really dislike the smell of vinegar, so thought I would give this a try.When cleaning, this product, mixed with water, gets pumped up through the hot water heater, and comes out the other side, back into the bucket. I read to let it run for about half an hour, which I did. It started as a cloudy solution, and after half an hour was a clear fluid, with a slight bluish tint. I did not notice any odor at all. When I did open the container of this powder, there were some big clumps, so did have to break it up with a screwdriver to get it out of the container, but not a big deal. Once I added water it quickly all dissolved.Once I was done, I let the cold water run through and out into the bucket, took about 2-3 gallons until that water was clear, then closed back up everything, and put all valves back where I had found them. This morning had a nice hot shower, so seems to be working fine.It is hard to say "This worked" because it is preventing a potential future problem. There was some "gunk" around the rim of my bucket when I was done, so although I didn't see anything in the water, it hopefully dissolved some scale and other stuff as it cleaned inside. I guess the only way for me to confirm it working is to do this every year, and see if the water heater lasts longer than my last and when it does to see how much buildup it has. It might lower by gas use slightly (easier to heat water), but on demand water heaters use so little gas anyway, would be impossible for me to see any significant change and attribute it to this cleaning.But it was easy to use, probably did what it was designed to do, and didn't have an odor. Hopefully it will extend the life of our unit.

Works great. I let it run for more than 20 minutes. I use boiling water.

Worked way better than regular Vinegar.

Worked great. Cleaned my heater. Would buy again. It's cleaner for a tankless water heater. What more can I say? It didn't sing songs or dance but it DID descale my heater.

Let me tell you about this magical little potion called the Rectorseal Calci-Free Tankless Water Heater Flush. First off, the name is a mouthful – it's like they couldn't decide whether to call it a flush, a descaler, or a fancy spa treatment for your water heater.When you open the tub, it looks like a batch of those fizzy bath bombs that are all the rage these days. But instead of turning your tub into a lavender-scented oasis, this stuff is going to give your tankless water heater the deep cleaning it deserves. And let's be real, those things probably need it after all the hot water abuse we put them through.The instructions are simple enough: dump it in, let it do its magic, and boom – your water heater is as good as new. No more weird buildup or funky smells when you turn on the shower. Just pure, unadulterated hot water goodness.Now, I know what you're thinking: "But wait, couldn't I just use some good old-fashioned vinegar for this?" Sure, you could. But where's the fun in that? The Rectorseal Calci-Free is like the spa day your water heater never knew it needed. It's like a deep tissue massage for all those hard-to-reach places.And let's not forget the best part: you don't even have to get your hands dirty. Just toss it in and let the little fizzy guys go to town. It's like having a tiny cleaning crew working tirelessly inside your water heater.So, if you're tired of dealing with mineral buildup and want to give your tankless water heater the royal treatment, do yourself a favor and grab some Rectorseal Calci-Free.

I followed the directions and it cleaned it out thoroughly, but unfortunately the next day the water heater developed a pinhole leak in one of the copper pipes, resulting in my basement flooding. Fortunately, the tankless water heater was under warranty but it was only 18 months old. I used this on the 2nd cleaning, which was the first time using this product. The first cleaning was done by a professional. Word of caution, place a water alarm below all tankless water heaters.

it does flush out a lot of dirty stuff from my tank. I didn't take picture, but water black/blueish after 40min.