self-cleaning water heaters

Nov 07, 2009 16 Replies

I see Home Depot has a line of GE/Rheem gas water heaters:


  • 40 gallon, 6 year warranty, 8
  • 38 gallon, 9 year warranty, self-cleaning, 8
  • 40 gallon, 12 year warranty, self-cleaning, 8

Other specs seem the same.



My question is, what does this self-cleaning mean, and is it likely that the extra bucks for the 12-year is a good investment?


(given that I'll also be paying to have them install it, which given venting and access issues will at least double the cost, the extra $80 isn't a big deal, but I'm still curious about it)


Water heaters are prone to sediment buildup that slows flow and causes other problems over time. The self cleaning eliminates the need for draining the bottom to clear the sediment. Has to do with the way the water circulates in the tank.

Does it make a difference? Worth the price? That depends on the quality of your water and how much solids can separate into the tank.

Is the 12 year a better deal? If you assume the heater will last the warranty period, the annual cost of ownership is a bit less.

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The self cleaning units, if I remember correctly, have a cold water supply tube that goes all the way to the bottom of the tank and is curved in such a way that it swirls the water around which keeps the sediment stirred up so it goes out with the hot water.

TDD

Heh, just what I wanted to know! High tech at it's best!

I presume it works somewhat, at least sounds like it can do no harm.

Thanks.

J.

You're welcome, I know a little bit about how stuff works.

*snicker*

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There is some debate about whether or not the feature is effective at reducing sediment.

TDD

The "self cleaning" means it has a "turbulator" inlet - basically the inlet tube goes to the bottom of the tank and then makes an arc around the outer circumference of the tank - water coming in agitates the water in the bottom of the tank reducing sediment deposits.

As for the 9 vs 12 year warranty it's basically just a better "insurance policy" - tank is in most respects the same. Might have an additional anode in the 12 year tank. For less than $30 a year I'd be REAL tempted to spring for the 12 year tank.

JRStern wrote in news: snipped-for-privacy@4ax.com:

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And none of them qualify for a tax credit. Doing some .gov clicking I learned that standard storage tanks pretty much don't qualify. Gas, Oil and Propane Water Heaters need to have an Energy Factor >= 0.82 or a thermal efficiency of at least 90%. The 3 referenced are in the .6 range.

And here's a list of a shitload (specific unit of measurement back in VT) of storage water heaters. They're all in the .6 range. Pretty handy for lots of comparisons besides EF too.

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From:

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1) Storage tank

Most storage tank water heaters can not qualify for the tax credit because they can not meet the Energy Factor requirement of .82. However, there are some commercial storage tank water heaters that can qualify for the tax credit because they have a thermal efficiency of greater than 90%. These models are larger than what is typically considered a residential unit and may not have the standard safety features of residential models.

Yes, it works. Just checked mine after 10 years. No sediment came out of the drain.

10 yrs? Who is the manufacturer, that's a pretty good life span. And, what was the HW tank rated in # of yrs to begin with? Thanks.

9 year warrantee Sears Kenmore Power Miser 9 40 gallon

vertex now quaifies for the tax credit, 1500 bucks installed around here

That sounds like mine (not self-cleaning). Sediment was there, but no sediment came out of the drain because the drain valve's water pathway is too small and angular to allow the sediment to come out. :-)

(it seemed to be about 1/4" x 1/4" in places - so all it takes is for a flake of scale larger than that to fall to the bottom of the tank, and nothing will escape the drain valve except water - giving the impression that there's no sediment in there)

some areas get no sediment, till the lining fails..........

Self cleaning means you pay more and it dies anyway..

You been checking it every six months or so, to see if sediment gets started?

In Southern Arizona, our water contains a high degree of "gypsum". Leave a glass of water out overnight, and there's a white sediment on the bottom.

In water heaters, this builds up to a "paste" that can't be flushed out using the water heater drain. In time, the water heater must be replaced.

A heater with a "swirl" would lift the sediment so it'd go out with the hot water.

I suspect you can still back-flush it, or remove the lower element and scrape it with something - it might not get it all, but if it's done every once in a while (annually, say) it can probably be done well enough to extend the life of the tank considerably - up until the point that the tank outright fails, I suppose.

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