Atwood Water Heater Leak Enigma

[1bigmess]

Sold the used for $100? Please, tell us where you sold it.

[mel s]

Originally Posted by Goostew65

I purchased a brand new Atwood 6-gallon water heater for $339 (free shipping), took the other one out, put the new one in, and after a skinned knuckle, presto, perfectly working water heater! No leaks! I managed to sell the other one for $100, so I figure I did okay. Thanks for all the suggestions and replies. Since I am responsible for this water heater, I will take great care to make sure it is winterized, etc. Thanks again!

Goostew65
For some reason it doesn't surprise me at all that your brand new Atwood 6-gallon water heater is "presto, perfectly working".
Mel
'96 Safari

[bailiff]

Ok, I'll add my 2 cents into this. My friend ordered a new Allegro and joined us during her maiden voyage. After supper that night, she returned to her site to walk her dogs. She discovered the floor covered with water. Another friend of ours assisted her in finding the leak. After removing some foam from the water heater, the seam was leaking. What made her mad as a hornets nest was, the tank had been repaired by the WH manufacturer and sent on to Tiffin. We could see a chalk circle around the repaired weld where the tank continued to leak.

[Cat]

I had several atwood water tanks crack at the seam. The problem is if you have a water pressure regulator that is too small. The regulator will keep your tank pressure at its rated setting say 50 psi when not using any water in the coach. But if you start using the water in the coach the pressure drops to 25psi because the regulator can not keep up / allow enough flow through it to keep the pressure steady. This causes the water tank to flex evey time the pressure drops and returns to the higher setting- old term "oil canning". The causes a fatigue crack right at the weld seam on the tank.
I replaced 3 tanks in 18 months. I went to a lager capacity(more flow) water pressurer regulator.
If you want to see if this your problem put pressure gauge on inside water lines- check the pressure with all faucets closed then open and see the difference in pressure. Had the motorhome 3 more years with the larger regulator no more problems.

[Cat]

I had several atwood water tanks crack at the seam. The problem is if you have a water pressure regulator that is too small. The regulator will keep your tank pressure at its rated setting say 50 psi when not using any water in the coach. But if you start using the water in the coach the pressure drops to 25psi because the regulator can not keep up / allow enough flow through it to keep the pressure steady. This causes the water tank to flex evey time the pressure drops and returns to the higher setting- old term "oil canning". The causes a fatigue crack right at the weld seam on the tank.
I replaced 3 tanks in 18 months. I went to a lager capacity(more flow) water pressurer regulator.
If you want to see if this your problem put pressure gauge on inside water lines- check the pressure with all faucets closed then open and see the difference in pressure. Had the motorhome 3 more years with the larger regulator no more problems.

[Old-Biscuit]

Originally Posted by Cat

I had several atwood water tanks crack at the seam. The problem is if you have a water pressure regulator that is too small. The regulator will keep your tank pressure at its rated setting say 50 psi when not using any water in the coach. But if you start using the water in the coach the pressure drops to 25psi because the regulator can not keep up / allow enough flow through it to keep the pressure steady. This causes the water tank to flex evey time the pressure drops and returns to the higher setting- old term "oil canning". The causes a fatigue crack right at the weld seam on the tank.
I replaced 3 tanks in 18 months. I went to a lager capacity(more flow) water pressurer regulator.
If you want to see if this your problem put pressure gauge on inside water lines- check the pressure with all faucets closed then open and see the difference in pressure. Had the motorhome 3 more years with the larger regulator no more problems.

In order for a pressure vessel to be affected it would have to be subjected to a 'Vacuum' not lower psi/flow

WH Tank can not be subjected to a vacuum when water is flowing out of a faucet at lower psi etc.

WH Tank is not susceptible to that type of 'flexing'
It will Burst from over pressurization but T&P would have to fail (opens at 150PSI)
It will Burst from forces exerted by frozen tank of water
It would crush (implode) IF a vacuum could be pulled on it as it is built for pressure not vacuum

But lower water psi/flow is not/was not the cause of your WH tank failures.

[BFlinn181]

I've got to agree with Old-Biscuit, A WH tank is much too robust to 'oil can' and flex itself to failure. Poor quality control of an automatic welder could cause a seam leak, but the fluctuations of a water pressure regulator couldn't flex a WH tank to failure. Many other components of the plumbing system would cause problems before a WH tank failure.

To suggest it's a flexing tank suggests a failure that's just not possible and starts 'stories' about Atwood water heaters that should be put to rest before it gets spread. It also does little to help the OP with their issue and just adds more internet confusion to their original post.

[Cat]

Hahahahah pressure won't make a tank flex. Think about the internal area of the tank. Square inches then multiple times say a 25 psi change.
I said nothing about Atwood being poorly made you did= poor welds. I blamed my repeat failures on me having a small water pressure regulator. I will also point out I had three failures of the tank at the weld in 18 months after I went to a larger regulator I had no more failures over several years.

This forum to is to help people with problems others may have had and to let them know what they did to fix them. I had this problem, a fairly pricey problem, my fix was successful.I let them know.
Pressure wont cause a tank to flex HAHAHAHAH

[1bigmess]

Flex | Definition of Flex by Merriam-Webster

[Cat]

I didn't realize I was writing for a technical journal.
How about the pressure increases and decreases or pressure fluctuations will cause the tank to expand and contract, causing a fatigue fracture to occur at the weakest point or where there is change in thickness or radius causing a concentration of stress. I think most people understood the point.

[Old-Biscuit]

Originally Posted by Cat

I didn't realize I was writing for a technical journal.
How about the pressure increases and decreases or pressure fluctuations will cause the tank to expand and contract, causing a fatigue fracture to occur at the weakest point or where there is change in thickness or radius causing a concentration of stress. I think most people understood the point.

It's your story so it works for you.........

I'll leave it at that.

[1bigmess]

Originally Posted by Cat

I didn't realize I was writing for a technical journal.

Originally Posted by Cat

Hahahahah
SNIP
HAHAHAHAH

Indeed.