Greenish sludgy stuff in water heater tank

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BobW44

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Hi all, Great forum, lot's of knowledgeble info floating around. It has helped me a great deal in my homeowner maintenance quests.
Well, today I drained the tank to replace the gas control valve. While I had the tank drained, I decided to replace the anode rod. Of course, I shut off the natural gas, water supply, and electric before I got started.

After draining the water tank, I removed the anode rod. All that was left was a bare wire. Glad I decided to check it.

After removing the gas valve, which also threads into the tank for the thermistor, I noticed quite a bit of greenish sludge in the tank. It had the consistency of whipped cream, light and flluffy. There appears to be quite a lot of it in the tank. It even was all over the thermistor probe.

What's is this stuff and how do I remove it?
 

Kingsotall

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Sounds like sediment. Most times it is not rock hard material but soft and almost slimy. Bluish green color. Need to flush the tank.
 

BobW44

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Thanks, A Wet-N-Dry Vacuum and numerous flushes pretty much cleaned it out.

After cleaning, I aimed a flashlight down the anode-rod-hole to illuminate the bottom of the tank as I looked in through hole at the bottom. Lo and behold, the old anode rod (or what was left of it) is lying on the bottom. I guess it dislodged from the wire-core as it aged. I tried to remove it but it was too difficult, (since I was working through the 1" hole)

Is this old anode rod ok to just lie on the bottom of the tank? I hope so.

Anyway, I installed the gas valve/thermostat, the new anode rod, and re-installed the blower. Reconnected the gas line, turned on the gas, and did a few snoop checks. Everything checked out, and I'm back in business.
 

Kingsotall

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One of these might have done the trick:

grabbertool.jpg

Good luck to ya.
 

hj

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stuff

That sounds like what an old anode rod looks like before it becomes a bare wire. You probably scraped it off while removing the anode rod. A gas heater control does not have a thermistor, it has an Invar rod. But if you went to the trouble of completely disassembling the water heater, you would have been better off just replacing it.
 

Master Plumber Mark

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funky--- nasty stuff

I have seen lots of the stuff you are talking about...

I have always wondered about it...

considering that this sludge has to boil and bubble to be able to heat the water....it sort of makes a stew.....

it makes me wonder if these sediments or heavy metals
that boil in the bottom of the heater could cause different skin diseases????
 

Ladiesman271

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Tank water heaters end up being full of all sorts of crap and bacteria. That's why you are not supposed to ever use water from a water heater for cooking or for drinking.

Tankless water heaters are the way to go. At least they provide unlimited amounts of clean hot water.;)
 

hj

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heaters

quote; Tankless water heaters are the way to go. At least they provide unlimited amounts of clean hot water.;)

The "stuff" on the bottom of water heaters is caused by heating it, so where do you suppose the "stuff" from a tankless heater ends up?
 

Redwood

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quote; Tankless water heaters are the way to go. At least they provide unlimited amounts of clean hot water.;)

The "stuff" on the bottom of water heaters is caused by heating it, so where do you suppose the "stuff" from a tankless heater ends up?

I think last time Laddyboy was asked that he disappeared for a 3 months... :eek:
 

TedL

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Tankless water heaters are the way to go. At least they provide unlimited amounts of clean hot water.;)

If that were true, they would be a much more compelling buy. But the truth is they provide a very limited amount of hot water, albeit for essentially...forever.

But if you routinely have more than one person showering at the same time, or doing anything that uses more than a trivial amount of hot water, there will be much disappointment.
 

SewerRatz

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If that were true, they would be a much more compelling buy. But the truth is they provide a very limited amount of hot water, albeit for essentially...forever.

But if you routinely have more than one person showering at the same time, or doing anything that uses more than a trivial amount of hot water, there will be much disappointment.

Unless you install the right sized unit or units to properly fit the demand of the house. I get way to many calls from people wanting the smallest advertised unit stating thats all the currently need. I try to explain to them that what if they get a house full of people and need all three showers to run at once. Or if he sells the home to a larger family.
 

Master Plumber Mark

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pros and cons

I hate to admit it, but ladyboy does have a point about
the sludge in the bottom of the heaters....


it is pretty nasty, and it makes me wonder exactly what is in that crap...

I wish I had my camera with me when we took out a number of extra nasty ones....
it looked like someone puked up green slime all over their driveway....
it took well over 10 minutes to wash it all off....
and the mess it makes in your truck when the load shifts,
can be a lot of fun ....




Actually, that is about the only positive thing I can
think of about the tankless heaters....


no one ever cares to flush and
service their water heaters becasue they are so troble free...
 
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Master Plumber Mark

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thank you

IMO most of it is scale from hard water and the fluffy pasty stuff off the anode rod.

Tankless water heaters have a minimum hardness level and many will have a water softener in front of them to meet the minimum hardness allowed.

Green is usually copper. Slimy is bacteria.

now the next thing that makes me wonder is.....

what kinds of bacteria???

I assume it is inert or it would have already caused an uproar decades ago....??
 

Ladiesman271

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If that were true, they would be a much more compelling buy. But the truth is they provide a very limited amount of hot water, albeit for essentially...forever.

But if you routinely have more than one person showering at the same time, or doing anything that uses more than a trivial amount of hot water, there will be much disappointment.



You guys should update your thinking. Two people taking a shower at the same time is not a good thing to do. You should also use a lower flow shower head than your use!


Instructional video of the volume of hot water that is required by code for two people taking a shower at the same time being demonstated by a few old school licensed plumbers
 

Gary Slusser

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now the next thing that makes me wonder is.....

what kinds of bacteria???

I assume it is inert or it would have already caused an uproar decades ago....??
Reducing types, Legionella and all that can survive in the heated water. Reducing types are harmless. Legionella is dangerous.

Turning up the temp to 140f kills them all.
 

SewerRatz

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Reducing types, Legionella and all that can survive in the heated water. Reducing types are harmless. Legionella is dangerous.

Turning up the temp to 140f kills them all.

Legionella requires the water to be 170º It is to hot to be safe in a home. If you want to keep the water hot to prevent stuff from growing in the tank, then you will need to put a whole hose thermal mixing valve to keep the output temperature at a safe level, along with other safety devices.
 

Redwood

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Temperature affects the survival of Legionella, as follows:

At 60 °C (140 °F) - Legionella dies instantly - pasteurisation occurs.
At 55 °C (131 °F) - 95% die
50 to 55 °C (122 to 131 °F) - Can survive but do not multiply
35 to 46 °C (95 to 115 °F) - Ideal growth range
20 to 50 °C (68 to 122 °F) - Growth range
Below 20 °C (68 °F) - Can survive but are dormant, even below freezing

From published Health and Safety Executive guidance for employers in the United Kingdom http://en.wikipedia.org/wiki/Legionella

!40 Degrees F is the requied temperature to kill Legionella Bacteria.
 

SewerRatz

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A minimum temperature of 60°C is required to kill Legionella bacteria in hot water systems (the higher the temperature the shorter the required contact time)

I got that from www.Legionella.org Here is an intresting little tidbit from their site as well about Tankless water haters. Note they flash the water to 190º then temper it back down, then learned the leginella was growing in the pipes downstream from the heaters.

Would you be able to comment on tankless heaters and the efficacy of holding them to a standard promulgated specifically to reduce Legionella risk?
We once thought, as you suggested, that elimination of the large volume hot water heater would significantly reduce Legionella colonization in the hot water system. In a survey of 15 hospitals in western Pennsylvania, in 2 hospitals with instantaneous steam heating systems (tankless heaters) no Legionella was isolated from these hospitals. We then replaced the 1000+ gallon hot water tanks in one of our VA hospitals with instantaneous heaters in an effort to decrease Legionella colonization. These heaters flash heated the cold water to 190o and then blended the water back down to the pre-set temperature (which was 140oF). Disappointingly, this installation had virtually no effect on the downstream colonization of fixtures. We now understand that the entire network of pipes is coated with a slime layer (biofilm) within which Legionella resided. The bulk of the Legionella colonization of the water system was downstream of the hot water tanks! This is why active disinfection throughout the system is required to control Legionella bacteria in warm water systems. So, if the temperature of the blended water as it exits from the tankless heater is 140oF, then that should satisfy the Health Department’s objective.​
 

Ladiesman271

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Tankless standby temperatures are room temperature. Old and stagnant water is 100% flushed out of the heater every time it is used. After the water heating cycle, a tankless will also heat the water in the heater above 140 degrees.


Tank water heater and distribution system temperature recommendations are listed here.


OSHA recommendations




DOMESTIC HOT-WATER SYSTEMS.


Background. Domestic hot-water systems are frequently linked to Legionnaires' outbreaks. The term "domestic" applies to all nonprocess water used for lavatories, showers, drinking fountains, etc., in commercial, residential, and industrial settings. Disease transmission from domestic hot water may be by inhalation or aspiration of Legionella-contaminated aerosolized water. Water heaters that are maintained below 60°C (140°F) and contain scale and sediment tend to harbor the bacteria and provide essential nutrients for commensal micro-organisms that foster growth of L. pneumophila. Large water heaters like those used in hospitals or industrial settings frequently contain cool zones near the base where cold water enters and scale and sediment accumulate. The temperature and sediment in these zones can provide ideal conditions for amplification of the organism. Dead legs (i.e., sections of piping or plumbing that have been altered or capped such that water cannot flow through) and nonrecirculated plumbing lines that allow hot water to stagnate also provide areas for growth of the organism.


Design. Water systems designed to recirculate water and minimize dead legs will reduce stagnation. If potential for scalding exists, appropriate, fail-safe scald-protection equipment should be employed. For example, pressure-independent, thermostatic mixing valves at delivery points can reduce delivery temperatures. Point-of-use water heaters can eliminate stagnation of hot water in infrequently used lines. Proper insulation of hot-water lines and heat tracing of specific lines can help maintain distribution and delivery temperatures.


Maintenance.

a. To minimize the growth of Legionella in the system, domestic hot water should be stored at a minimum of 60°C (140°F) and delivered at a minimum of 50°C (122°F) to all outlets. The hot-water tank should be drained periodically to remove scale and sediment and cleaned with chlorine solution if possible. The tank must be thoroughly rinsed to remove excess chlorine before reuse.

b. Eliminate dead legs when possible, or install heat tracing to maintain 50°C (122°F) in the lines. Rubber or silicone gaskets provide nutrients for the bacteria, and removing them will help control growth of the organism. Frequent flushing of these lines should also reduce growth.

c. Domestic hot-water recirculation pumps should run continuously. They should be excluded from energy conservation measures.


Control.

a. Raising the water-heater temperature can control or eliminate Legionella growth. Pasteurize the hot water system by raising the water-heater temperature to a minimum of 70°C (158°F) for 24 hours and then flushing each outlet for 20 minutes. It is important to flush all taps with the hot water because stagnant areas can "re-seed" the system. Exercise caution to avoid serious burns from the high water temperatures used in Pasteurization.

b. Periodic chlorination of the system at the tank to produce 10 ppm free residual chlorine and flushing of all taps until a distinct odor of chlorine is evident is another means of control. In-line chlorinators can be installed in the hot water line; however, chlorine is quite corrosive and will shorten the service life of metal plumbing. Control of the pH is extremely important to ensure that there is adequate residual chlorine in the system.

c. Alternative means to control Legionella growth include the use of metal ions such as copper or silver (which have a biocidal effect) in solution. Ozonization injects ozone into the water. Ultraviolet (UV) radiation also kills microorganisms. Commercial, in-line UV systems are effective and can be installed on incoming water lines or on recirculating systems, but stagnant zones may diminish the effectiveness of this treatment. Scale buildup on the UV lamp surface can rapidly reduce light intensity and requires frequent maintenance to ensure effective operation.
 
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