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Flushing out the water heater


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Five years ago, I installed in my house a new Navien 240 LP tankless water heater with the built in circulator. No regrets whatsoever. What I and others didn't realize at the time, was how bad the water going through it was. It's bad water everywhere in this area and we've since put together an aggressive service agenda to alleviate problems associated with water quality and our customers' water heaters. But back to the story at hand, I realized I never flushed my water heater; tankless water heaters should be flushed every year or two with cleaning vinegar. It's a simple task since the valves installed on them allow it to be isolated and garden hose connection for pumping vinegar through.

I had never flushed mine out so I thought I better pump some vinegar through, then let it sit for the majority of the day, then flush it out with clean water.

What else would I have expected than this I guess I shouldn't be surprised:


The following is a humorous text between myself and a coworker who is known for taking a dump in buckets when he gets desperate; [emoji1]


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Switching from electric tank water heater to gas tankless requires venting for intake and exhaust (2" pvc sch. 40) a gas supply, and 120v instead of 240v, plus it's wall mounted. It's frees up a lot of room, you can mount it up higher if you like to access the underside of it, which is where you will flush it out at. Get tankless valve/unions for it so it can be isolated when it needs to be serviced.

Mine has a 12 year heat exchanger warranty and 3 year parts I think.

I think flushing is super easy, I have a small utility pump, three washing machine hoses, a bucket, and 2 gallons of cleaning vinegar. Why I didnt do it sooner, well, no excuses I guess.


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You should flush any hot water tank out, but I believe 99% of the population never does it. The big thing with tanked water heaters is if you want a longer life is to replace the sacrificial anode it keeps to tank from corroding. That is another thing people never do. The one thing Protool is if you go Electrical Tankless is you need to run some serious amperage from the panel to the unit. I don't know if electric tank less units are worth it with the increased power draw and the cost of installation. The one thing is new water heaters are bigger because they added more insulation to make them more energy efficient, so some water heaters won't fit in their old locations. You either have to find a new old stock water heater or a lightly used one if you want a direct replacement. They also make ones that fit, but they don't have as much tank capacity.

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