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Old 11-03-2019, 12:26 PM
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Default Hot Water Tank Maintenance advice

I sit on the board of a Housing COOP of 18 housing units. 40Gal Bradford White Defender series Hot water tanks were installed in Dec 2008.

One of the other board members has a brother who is a plumber who wants to change out the anode rods on all the 18 tanks.
I know for certain that the anode rods have never been changed since install.

I am opposed to the decision and expenditure on the basis that if a anode rod provides 3-4 years of cathodic protection then these tanks have been at risk of increased corrosion for the last 7-8 years.

I would prefer to start fresh with a more rigorous maintenance schedule once new tanks are installed in the future. Could be tomorrow or in a few years. I have no crystal ball. This and regular scheduled flushing make sense to me.

Is there anything to be gained in this case in terms of tank longevity by changing anode rods for the first time at 11 years in?
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Old 11-03-2019, 12:43 PM
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I've been a plumber for nearly 20 years including 8 as a service technician. I did a little experiment on tanks that had failed. I pulled the anode rod out of a dozen tanks that went. The anode rod was still in tact in all of them. I've never changed out an anode rod in any tank ever. If you installed residential tanks in 2008, you're only going to get a few more years no matter what you do. My best advice if you want to try to extend their life is unscrew the factory drain fitting. Screw in a 3/4" brass nipple, full port ball valve and garden hose adaptor. That's your best bet for getting some of the sediment out and its the buildup of sediment that causes the tank to fail. The more sediment that's sitting on the bottom, the sooner they fail. Even that won't get it all out, but it's at least something.

Some plumbers will tell you to test the T&P valve by pulling up on the tab. They only tell you that so they can sell you a new T&P since they never really seat again...

All of this is just my humble opinion. I think you'd to better to put the money you would spend on the new anodes and install on budgeting towards new tanks down the road.
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Old 11-03-2019, 01:04 PM
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Originally Posted by omega50 View Post
Is there anything to be gained in this case in terms of tank longevity by changing anode rods for the first time at 11 years in?
A lot depends on your water. I owned a house in Wetaskiwin many years ago. When I bought it the hot water tanks was a few years old, I'm not sure how many. I lived in the house for 14 years and never flushed the tank or changed an anode. It was still working fine when I sold the house.

When I lived in High Level, even with flushing the tank twice a year the best one could hope for was five to six years before the tank would start leaking. I never got around to changing an anode there.
All the neighbors I talked to about this told of similar experiences.

We've lived in this place for eight years. This tank was two years old when we bought the place. We flush the tank at least once a year but have not change a anode yet. This tank is now ten years old. NO issues yet.
I plan on changing the anodes next year. That will tell me how long they will last, by seeing how much the present anodes are eroded.

I can't answer your question. I don't know what the water is like there.

What I would do is talk to folks in the district who are on the same water supply. If I could get a handle on how long tanks last there, I'd change the anode at half the expected life.

There is nothing to be gained changing an anode before it's due, but there sure is if it's badly eroded.

I don't know if you understand what an anode does.
If you do fine, if not, for you and those who don't I'll try to explain it.

Your anode attracts electrolysis that would otherwise erode other parts of the tank. As it does this it erodes so that your tank does not.
So long as there is sufficient surface left for the anode to preform it's work, you are protected.

On our Ocean boat we change them out when they get down to 25 percent left. I expect that would work with a water tank since it's the same issue but to be safe (because you can't visually inspect them without taking them out) I'd change them at what I believed to be half life for the anode.

Reason being, anode are a lot less expensive then a tank.


Edit to add;

The parts of your tank most likely to be damaged by electrolysis are the heating elements, pipe fittings and welds. The rest of any good tank is protected by a anti corrosion coating.

I know this because I've cut old leaky tanks apart to make stock watering tanks out of them.
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Old 11-03-2019, 01:07 PM
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Still confused about tank failures. Often hear that tanks are glass lined. If true then how does glass corrode? Does it fracture and leak. Or is it enamel and chips just like my canner?

If sediments increase failure rates is it because temps get artifically high trapped under the scale and above the burner?
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Old 11-03-2019, 01:13 PM
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Originally Posted by omega50 View Post
Still confused about tank failures. Often hear that tanks are glass lined. If true then how does glass corrode? Does it fracture and leak. Or is enamel and chip like my canner?

If sediments increase failure rates is it because temps get artifically high trapped under the scale and above the burner?
see my edit.

I forgot to add, if the heating elements are failing it's a good indication you may have an electrolisis problem. Better check you anodes.

Sorry bout that. LOL
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Old 11-03-2019, 01:14 PM
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My experience pretty much mirrors thepilotcock's except in that I've changed a few residential anode's, but relatively few considering the 31 years I've been at it. Commercial tanks are more common for anode replacements, (sometimes I'm just changing them in insulated storage tanks that are simply volume storage with a circ pump) but then those type of buildings generally have management following established maintenance procedures.

I too like a full port ball valve on each heater drain attached with a short brass pipe nipple with a hose adapter and a screw on tethered cap & chain. New heaters have drain valves that need a tool (screwdriver or wrench) to actuate them to keep little people safe from the hot water, I tighten on the cap beyond hand-tight for this reason. The full-port valve allows for more rapid flushing of the tank which will stir up more sediment.

Some tanks with longer warranties come with dual anode rods, one will have its own threaded port in the tank and the other will be suspended from the hot water outlet nipple. These are available separately or as replacement items and can be beneficial. Some manufacturers or suppliers offer longer warranties where the only difference is paying more money for the warranty extension, no additional anode rod or such.

Last spring I had clients whose hot water was quite rusty, they had dual power-vented water heaters piped in series. I unscrewed the anode rods and each was dissolved down to a metal core rod which was the source of the rust (I was curious why it was not a stainless steel centre core, but I digress). I replaced the anodes and flushed the tanks repeatedly and they were OK, a good savings considering what a power vented 50 and a power vented 75 would have run them combined. (I may sell them a boiler and stainless indirect heater when they do cave on them, its a bit of an odd set-up presently with one heater upstream of the 2nd serving their floor heat). Anyways, the reason their anodes were so corroded was their excessively aggressive water softener, it was amusing as my product rep for their brand of water heater immediately asked if they had a Kinetico softener when I described their anode condition, so its a known issue. The house was not that old, I think perhaps 6 years in a nice neighborhood (West Springs).
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Old 11-03-2019, 01:20 PM
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Originally Posted by omega50 View Post
Still confused about tank failures. Often hear that tanks are glass lined. If true then how does glass corrode? Does it fracture and leak. Or is enamel and chip like my canner?

If sediments increase failure rates is it because temps get artifically high trapped under the scale and above the burner?
The enamel will crack and sometimes not adhere well initially due to welding slag or such. As they're subject to varying pressure and the occasional on/off with the water supply that can also affect the enamel, sometimes you can hear a pinging noise when restoring water pressure. The enamel lining is much like enamel campware and all that entails; some sticks well, sometimes you get one with a flaw.

You can tell there is a scale accumulation if you hear a rumbling sound when its firing, that's the water in the sediment coming to a boil but then rapidly cooling when it hits the other water above. This phenomenon is why the scale generally stays 'flaky' or sand like, it can't stay stuck because it eventually gets loosened by that super-brief boiling before mixing with the water above.
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Old 11-03-2019, 01:33 PM
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Having training in radio electronics come in handy some times.

A bit about electrolysis. And why some anodes never erode.

Electrolysis is what happens in your car battery to produce current.
In other words, it's a chemical action that produces electricity.

Salt water has chemicals in it that support electrolysis, some tap water does too. And some does not.

In effect, where tap water is high in minerals it can act like a battery. Chemicals (mainly salts) in the water react with some metals in the tank to create this current, in so doing they erode that metal.

This is why some water softeners erode your anodes.

Lead supports this reaction but does not erode, so does zinc which is what an anode is made of, but it does erode.

Other metals such as iron also support electrolysis and erode but zinc does it better so it erodes first. Thereby protecting other exposed metals.

I won't get into why a car battery fails except to say the culprit is not erosion.
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Old 11-03-2019, 02:23 PM
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Typically I can accurately forecast the failure of my hot water tank by having new Berber Carpet installed in the basement Rec Room earlier in the day.
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Old 11-03-2019, 08:03 PM
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I think everyone should change their water heater twice a year when they change their smoke detector batteries.
That's a thing, right?
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Old 11-03-2019, 09:28 PM
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I think everyone should change their water heater twice a year when they change their smoke detector batteries.
That's a thing, right?
I'd be happy with once every two years!

Which just reminded me of the old water softeners I used to see that were swapped out on some schedule rather than regenerating automatically by themselves, I'm not sure of the time rotation but I think they were from Culligan. What a job that would be dragging those in and out up and down the stairs all shift, every day.
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Old 11-04-2019, 03:20 PM
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Originally Posted by KegRiver View Post
Having training in radio electronics come in handy some times.

A bit about electrolysis. And why some anodes never erode.

Electrolysis is what happens in your car battery to produce current.
In other words, it's a chemical action that produces electricity.

Salt water has chemicals in it that support electrolysis, some tap water does too. And some does not.

In effect, where tap water is high in minerals it can act like a battery. Chemicals (mainly salts) in the water react with some metals in the tank to create this current, in so doing they erode that metal.

This is why some water softeners erode your anodes.

Lead supports this reaction but does not erode, so does zinc which is what an anode is made of, but it does erode.

Other metals such as iron also support electrolysis and erode but zinc does it better so it erodes first. Thereby protecting other exposed metals.

I won't get into why a car battery fails except to say the culprit is not erosion.
I would suggest you stick to radio electronics because what you wrote is extremely confusing and just plain wrong. Case in point do you know the difference between erode (erosion) and corrode (corrosion)?
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Old 11-04-2019, 06:09 PM
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So is it really practical to change the anode with Calgary’s hard water? Sediment builds up so fast I never expect my tank to last more than a dozen years.

Dodger.
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Old 11-04-2019, 06:22 PM
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I see tanks lasting anywhere from 8-22 years in Calgary (average, I see ones go within warranty and others older yet). I've seen much older tanks but there seems to be a wide variance in how long they last. This is the span they'll last with nothing done to their anode rods so it begs the question, how long would they have lasted with a new anode at 8-10 years? It's an unknown....

I peg the average age around 15 years based on the ones I take out.

I once changed on that was 39 years old when I was 31, the blasted thing was older than me. That one was in Bowness with a very old gent who probably didn't use much water.

I saw one that was probably 40+ years old in a house in Mt Royal and I wanted to change that thing something fierce as based on the label; I had the impression that the entire pressure vessel was copper..... That would have been a nice bonus, though I'd have had the conundrum of building something creative out of the stripped pressure vessel or taking it in for scrap. It would have had a ridiculous amount of scale in it as the house didn't have a softener. My work there was on the boiler so it wasn't on my task list.
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Old 11-04-2019, 11:32 PM
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I would suggest you stick to radio electronics because what you wrote is extremely confusing and just plain wrong. Case in point do you know the difference between erode (erosion) and corrode (corrosion)?
Yes I do, do you? Anodes erode, not corrode.

Erode is to carry away, corrode is to destroy by chemical action.

The metal in an anode is carried away by electricity generated by chemical action. Much like electroplating, a very similar chemical reaction.

Corrosion changes the chemical structure of a substance, erosion simply removes a substance slowly, one molecule at a time.

Corroded aluminum still exists but in an altered state, IE; aluminum oxide.
Which adheres to the parent metal.
Eroded zinc from an anode still exists as zinc, but as particles of zinc in solution, not part of or attached to the parent metal.

At least that is what my text books said. Being that I am not a chemist nore an engineer, I can only take the text as truth since I have no other source of information.

If you have texts that say otherwise I would appreciate knowing what texts those are so I can correct the lessons I was taught.
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Old 11-05-2019, 07:28 AM
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Originally Posted by Newlyretired View Post
I would suggest you stick to radio electronics because what you wrote is extremely confusing and just plain wrong. Case in point do you know the difference between erode (erosion) and corrode (corrosion)?
Aren't you late for a magazine/clip argument somewhere?
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Old 11-05-2019, 08:05 AM
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check with your insurance company, some companies wont cover flood damage from a failed hot water tanks if it is older than 10 years
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Old 11-06-2019, 10:25 AM
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Originally Posted by KegRiver View Post
Yes I do, do you? Anodes erode, not corrode.

Erode is to carry away, corrode is to destroy by chemical action.

The metal in an anode is carried away by electricity generated by chemical action. Much like electroplating, a very similar chemical reaction.

Corrosion changes the chemical structure of a substance, erosion simply removes a substance slowly, one molecule at a time.

Corroded aluminum still exists but in an altered state, IE; aluminum oxide.
Which adheres to the parent metal.
Eroded zinc from an anode still exists as zinc, but as particles of zinc in solution, not part of or attached to the parent metal.

At least that is what my text books said. Being that I am not a chemist nore an engineer, I can only take the text as truth since I have no other source of information.

If you have texts that say otherwise I would appreciate knowing what texts those are so I can correct the lessons I was taught.
Corrosion is a chemical reaction, while erosion is a physical action. What you described is a chemical reaction and therefore corrosion.
this simplifies the explanation of how an Anode works and please note that the metal used in an anode is molecular weaker than the metal it is protecting, thus it corrodes first.

Sacrificial anodes are used to protect metal structures from corroding. Sacrificial anodes work by oxidizing more quickly than the metal it is protecting, being consumed completely before the other metal reacts with the electrolytes
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Old 11-06-2019, 06:10 PM
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Corrosion is a chemical reaction, while erosion is a physical action. What you described is a chemical reaction and therefore corrosion.
this simplifies the explanation of how an Anode works and please note that the metal used in an anode is molecular weaker than the metal it is protecting, thus it corrodes first.

Sacrificial anodes are used to protect metal structures from corroding. Sacrificial anodes work by oxidizing more quickly than the metal it is protecting, being consumed completely before the other metal reacts with the electrolytes
I know what the internet says. And it does say it is corrosion.
And I'm sure many other people think the internet is always right.

One word. Anode.

Look it up. If you understood what an anode is you would understand why what I said is true. But you won't look it up will you.

One last thing, I doubt any of this will sway your opinion on the subject or about me.

The wording of your first post clearly tells me that you think you are superior to me. You are welcome to think that if it makes you happy.

The bottom line is I have no interest in pursuing this discussion any further. I see no point in it.
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