Water heater implosion

I've pulled a couple of water heaters in the last two weeks that have seemed to have swelled....


both have been Gas..


The nipples on top have turned in..... The Exaust has droped.....


Well anyways I've been told it is caused by excesseve pressure... I don't buy it.... They shoud be static tested to 300psi and the pop-0ff is at 150.....

any ideas on why they have such odvious stresses??????





dances-with-pumps

seen it often....

I run into that on occasion.....

usually with A.O.Smith heaters, it seems like the

nipples on top sort of bend inwards......

I think its high pressure , thermostat overheating,
and the T+P valve not working anymore at all.

But the seams of the heater never burst
so it just sort of swells up like a baloon and eventually
just leaks instead of exploding......

Both of my water heater where bradford white's

just so you know. but none burst.... just sort of leaked.

Read this. The problem is caused by high pressure. I've seen it a zillion times, and almost always associated with a do it yourselfer re-using the ond T&P, or plugging it.

I have to tell you that I have been in the hot water business for over 20 years, and have replaced thousands and thousands of heaters. I've never seen one rupture like those two in the photos. All I can say is wow. Can't wait to show those photos to my parters and employees!

Thanks for the info


one of the water heaters had a PRV.... the other I could find no reason for it to be a closed system.....not to say it wasn't hiden in the wall....


the T&P should relieve the pressure.... but I shouldn't rely on it?


OK I'll watch for this and correct when I can.....



Thanks again



dances-with-pumps

I have had 2 similar to the above pics over the years but never bothered to open them up to look at the tank. They were bulged and leaking but had not let go totally.

bursting heaters

GOING TANKLESS....
those heaters are in my office window....
the Reliance heater still has a T+p valve on it...


It put a gas man in the hospital when it
exploded.....

the unit was rumblimg and bounceing on the floor
in an old ladies home one night
and this gas fellow went up to it and turned it down.....

when he touched the thermostat,
it blew up in his face and threw him across the room
scalded him over about 60% of his body...



never go up to a heater that is moveing and shakeing...

turn on the hot water and let it cool down first....


have you seen a 1915 Humphrey Side arm before??

its the original Tankless Water heater...

I'd love to see those heaters in person. I've never seen the old Humphrey except in photos. Yes, that guy is lucky to be alive. It sounds like he had a runaway, with a plugged T&P. When I encounter those, (only a few times in 20 years) I tell the customer to turn the power and or gas off and get out of the house. DO NOT touch the water faucets until it can cool off. Introducing cold water to the tank can have a "saturn rocket" effect on the heater. The incident in the article happened a few years ago, I was actually interviewed by the TV news team the day this happened. It launched and landed 400 feet away. A football field is 300 feet long.... YIKES. Some moron had capped the "leaking" T&P. I can just hear that guy... "hmmm i'll fix this leaking gizmo..."

Some years ago I went through A.O. Smith's service training program in Dallas Texas. In that class, they show a movie of how a water heater will launch. It's quite a show...

http://archives.seattletimes.nwsour...28m&date=20010728&query=water+heater+explodes

Mark,
Being I know nothing about these tanks, I need to ask you, when you said, to turn on the hot water, did not mean, turn it off?
I love antiques, that could be used in a room, as an admoire.

turn on the water...

I am of the opinion that it would be best
to cool down the heater by simply truning on
the hot water at the bathtub......

I have had to do this before once with a very old 80 gallon
electric water heater that was literally blasting
steam out of the lavatory faucets. when I arrived on the
scene.......

I just kept everyone a good distance away , turned on the
hot water at the tub and let the heater
cool down natrually .....it literally blew steam out of the tub faucet
for a few minutes......that sort of concerned me....

but it never took of like a rocket either.....

usually you are thinking pretty quickly on your feet
when you encounter a situatioin like that.....

wether its the right thing to do or not,
I am not really sure...

but I am still here and my skin is still intact...so who knows..

If you have steam only coming out of the faucet, the water has "superheated". At that point, you are at T minus 5 seconds to launch time. Its a good thing the pipes were big enough to allow enough steam to release. Introducing cold water to the heater can cause the explosion if the now expanding steam can't escape fast enough. You are right though, its hard to know exactly what to do sometimes.

It seems that you got very lucky. Superheated water is VERY dangerous.

This thread is scaring the heck out of me!! I installed an electric AO Smith yesterday. (for my own property, I am a DIY'er). I am super nervous about these tanks getting too hot. Are there a group of things that I should be checking on the water heater to insure this won't happen? Any safety advice will be very much appreciated. If you guys want to tell me that I am in over my head installing one of these than that's fine too! I will call a pro or an inspector to inspect the installation.

Thanks for all the advice on this great forum..
Molo

Molo If you are talking about the used heater you just installed , just change the T&P valve. They are supposed to be tested yearly anyway. If you like you can change the T stats also.

MPM, you are 1 lucky man. Sounds like you were seconds away from a new experience that you would rather not have had !!!!

Hello,
Yes, I am talking about the used heater I installed.
1. How do I test the current T&P relief valve?
2. Also, Can I replace the thermostats without draining the tank and pulling the elements? It appears that The elements might actually be holding a metal plate in place over the thermostats (thermostat plate).
3..What danger is there in not replacing the thermostats?
4.Is the concern that they will stay on and the tank will get too hot?

Thanks for all of the help,
Molo

The only easy check on a T&P valve is to see if the shaft is stuck by opening the valve and letting some water out. It should move smoothly with no binding. The hassle is, you can get some crud stuck on the seal and it will leak afterwards. Better to just replace it.

Verifying the pressure action or over-temp would require dissassembling the thing and hooking it up to test gear. Again, cheaper to just install a new one.

In theory, an electric water heater could have fusable links to shut off the power in an over-temp situation...don't know enough about them to know if they actually have one. That is normally the job of the thermostat, although a fusable link could be a backup (only works once, though!).

The electric water heater thermostats must have some way to stop the heating process. I'm just wondering if there's a way I could test the reliability of the thermostats, or if this is like the T&P valve (easier just to replace) I'm still thinking that I will have to drain the tank and pull the elements if replacing the thermostats is the direction I should go. I wonder if contacting AO Smith would help to clarify this issue.

Thanks,
Molo

Gas heaters thermostats use the fusable link method. Electric stats use whats called a "bi-metal disc" high limit. In either case, the high limit should open if the temperature exceeds 180 degrees. Should is the key word. After the high limit, of course you have the T&P, which should blow when the temperature exceeds 210 degrees. Should. The problem is that things fail. Thats why they want you to trip the T&P each year to make sure the mechanism isn't clogged or "rusted" shut. Like Jad said above, it usually results in letting some junk get under the seat and then the T&P will leak.

Do you replace the T&P and stats frequently? Its a good question. I'd probably recommend that you at a minimum trip the T&P to make sure it is not jammed up, and be ready for the leak that is likely to happen. If your heater is in good shape, and the stats remain in a nice clean moisture free environment, then they should be fine for years to come. Trouble with the stats usually shows up in the form of a tripped high limit. There is only one thing that trips a high limit. HIGH TEMPERATURE. That's the clue telling you to look for a problem, and fix it. If no problems can be found, REPLACE THE STATS. Period. I am constantly amazed at how many customer say they have been pressing the "red button" on the water heater now for months. The high limit reset is to be used once only, so you can have hot water while you wait for service. It will trip again, at least you hope it does... otherwise you have just started the countdown to potential "launch".

On the used heater, I definitely concur that the T&P and Stats should be replaced. The elements should be checked for grounding too. Stats can be replaced without draining. Just try to get the same style stats so the wires will reach.

Thanks tankless,

How do I check for grounding on the elements? Also, is there harm done in puching a reset button when it doesn't need to be? In other words, I pushed it when the water heater wasn't wired in yet.

Thanks,
Molo

molo said:

Thanks tankless,

How do I check for grounding on the elements? Also, is there harm done in puching a reset button when it doesn't need to be? In other words, I pushed it when the water heater wasn't wired in yet.

Thanks,
Molo

Click to expand...

No problem with pushing the reset like you mentioned. Pushing it just manually pops the bi-metal discs back into the closed position (or does nothing if it was already closed). Checking for a grounded element requires an ohm meter (i use analog for simplicity, but hard to find now). The heater must be full of water. Turn off the power, remove the wires from both elements. With the ohm meter in the continuity mode, put one lead to one post on the element, and the other lead to the metal of the tank. Scratch the metal a few times with the second lead to ensure a good contact. If you see the needle move, (or otherwise see "continuity") the element is grounded. Repeat the drill on both studs of both elements.

What does "grounded" mean? The outer sheath of the element has cracked and water is now getting inside the element to the filiment. It will work like this for some time. The problem with the grounded element (aside from a potential shocking problem) is that the element is now able to heat the water with 120 volts (normally takes 240). This is the second most common reason for a tripped high limit. A bad lower stat is #1. Others have suggested replacing the stats in pairs when there is a problem. I agree 100% with this theory. If in doubt, replace them both and be done with it.

And I always laugh when someone says they can use a meter to check the stats. It's impossible to check the stats with 100% certanty. Even the "heat it up" trick isn't reliable, because the act of removing the stats from their holders will oftentimes break the contact loose that had stuck closed. I like to prove the things I can prove ( elements are not grounded, and are drawing amps under voltage), and then proceed to the obvious conclusion.

Does the wat3er heater take 120 per element? Is this how you get to 240? I wired this heater in with 10-2 romex coming out of a 30amp breaker.

Molo