Gas Water Heater - Four Cracked Lines

Where is the crack? If it is at a pipe entry point, then I'd look at vibration/fatigue issues.
Del

The crack is in the liner inside - every time. I am wondering if the guy who installed them is "rough" and bangs the unit around while installing. I know that my door frames have taken some heavy hits from his work. This time, I plan to use a different plumber just to see if it makes a difference.

I don't think it's the temperature differential. Your supply line goes into the top of the heater, down through a tube, and exits near the bottom of the tank. The water gets somewhat preheated on the way down to the coolest water in the tank. Check your safety valve yearly, and don't use an old valve on a new heater. A stuck valve will blow the tank. You might need a small expansion tank, and check for water hammer.

I had an A O Smith heater that ate two electrodes, as well as tripping out frequently. I was kind of glad when the damn thing started leaking after five years, and replaced it with a Bradford White that is now 14 years old and no problems yet.

Both electric heaters.

Also look at furring-up issues. Magnesium and calcium carbonates (in particular) are inversely soluble in water. As the temperature goes up, they will tend to precipitate on heating surfaces, insulating them, and causing the surface temperature to increase.

If the water heater is NOT used for water to be ingested, then try upstream softening by ion exchange. The substitute for MgCO₃ and CaCO₃, Sodium chloride, is highly soluble in water at a wide range of temperatures.

Every water heater gets cold water ran into it. As that is what its for to heat water. If the water was hot it wouldn't need heating. And the water coming in from most water supplies can be pretty cold. I don,t think that would be the problem or we all face that problem.

I would look at the pressure that the recirculating pump may be placing on the tank. Maybe there is a restriction in the line that causing the pump to put pressure on the tank. That over time fatigues it.

Do you use a pressure reducer on the incoming side? This can act like a check valve.Is there a temp & pressure valve on the tank? If not, there is no means to relieve the pressure. I have seen where the cold water is heated in the tank and there is no way to relieve the pressure, the water pressure in the system in the system can rise. This can cause the hot water valves be hard to open and it could cause a tank failure. You could put a pressure gauge on the tank to measure pressure to see if overpressuring the system is causing tank failure.

SSkahn6, I'm going to echo the suspicion of vtbgiraud, since I think he is on the right track.

Defects and pressure are the two major causes of tank failure. We did not get any information in your post about the pressure incoming from the main source, and the fact that water heaters have a pressure relief valve testify to the need to be aware of what pressure is doing.

Once a temp/pressure relief valve has been operated, they can lose their validity from things as simple as the calcium build-up. If you are using a pressure reducing device it is a one-way device and should be coupled with a pressure relief valve and an expansion tank since there now exists a closed system. This would be separate from the valve on the water heater, and driven by pressure only. Avoid "testing" the valve, instead monitor the pressure inside the closed system by the addition of a water pressure guage to keep an eye on the pressure. It couldn't hurt to have a guage on the incoming pressure ahead of the pressure reducer.

The more information you have to work with, the better you will do in getting to the bottom of the cause. CJM

If you take a picture of the installation. Give me the specs on the pump, heaters, line sizes, length of run, and water pressure, I could probably come up with a reasonable cause for the problem and solution.The pump could definately be part of the problem, however, it could also (most likely) be water temperature shocking the tank due to rapid expansion and contraction.

What is the temperature of the water coming into the house?

Where do you live?

What is the demand for water in gpm?

Do you run out of hot water?

What temperature do you have the tank set at?

Is the tank gas or electric?

I have a system that will not crack due to the way it is piped, will never run out of hot water (as long as you pay the utility bill), will last about 20 years, and will reduce you energy bills about 40%.

You can e-mail me at rich@rgreenwald.com if you like.

Re:Four cracked liners.

You do not describe where the cracking occurs in the heater. Depending on the type of burner used there will be a temperature gradient across the vessel/tube section in keeping with the volume of products of combustion; ie open flued v pressure jet type. Does this heater have independant flue tubes through the water space or is all the heat transferred to the bottom and ouside surfaces as per the 'Andrews' design. Is there any sign of wasteage in the area of cracking? if there is you probabaly need a sacrificial anode to protect the shell.

Shut off the circulation pump. Wait and see if the problem goes away. You'll be saving money at the same time. While you are at it put in a tank-less hot water heater. You'll save a ton more of money. We are supposed to be conserving energy these days.

You may wish to change to an instantaneous water heater. They are more expensive, but you save energy since you are not heating up water due to the tanks thermal losses. The domestic hot water tank is one of the most inefficent devices ever installed.

I think either your plumber or someone that handled the hot water heater probably did it incorrectly and cracked it. If it is not near an inlet or outlet I would not think vibration could cause it. Although minerals in you heater can cause a build up that prevents heat transfer I have never seen this build up cause a crack. Is there some way you can check it before you put it in? I think this would be best and would at least answer a big question about the handling of the heater. I have a problem with servicemen not treating the stuff they work on or other equipment they work near like they should. I am doing a remodel project on a bathroom and the guys that put in my vanity tops did a very good job and literally destroyed some stained and varnished base moulding along the way. I caught one of them standing on it once and I had it stacked out of their way. I really think they did it on purpose because it is hard to believe anyone with the skills they had could be this stupid. In the end after they left I had to replace some of the base board trim at my cost.

I think you should consult the experts .

You will find them here David. Centuries of experience and practical wisdom reside on this forum. After 3 cracked tanks within a year, I found the pressure from the incoming supply was rising well over 120 psi at night. A pressure regulator, expansion tank & 75 psi relief valve (without heat release element, just pressure) ended the problem.

Thanks to everyone for your responses. We think we've determined it is a water pressure problem. Looks as if the pressure builds up overnight. During daytime it is 55, but under the overflow pipe from the pressure relief valve it is WET! Also, I keep finding water in that bathtub and sinks in the mornings, but no one was using them. Put in a new water heater and expansion tank this time, but will add a pressure regulator to incoming waterline as well after reading your posts.

Don't forget to also add an independent pressure relief valve on the user side of the pressure regulator. This valve should have a release setting lower than the 150# usually found on the heat/pressure relief valve of the water heater. This is because the pressure regulator creates a "trapped" water system, which can not back-flow back into the main supply line when the water heater expands the volume. The expansion tank is excellent, but has it's limits.

Have you checked your water for methane gas infiltration that added pressure could cause it.