Water heater/storage tank multiple failures

[Don H]

I have a geothermal heating system for the house which also heats my water. The system is set up so the heat exchanger in the geo furnace preheats well water and sends it to a 50 gal water heater used as a storage tank (not hooked up to electric), then over to a water heater with power to step up the temp before sending hot water out to the house.

The problem I'm having is that the storage water heater, the one without power has failed and started leaking water 2 times in the last 8 years. I'm now on my third water heater/storage tank.

Some other facts:
Previous (original) water heater lasted 28 years and was still working when they installed the new 50 gallon electric heaters with the geothermal system.
I have no problems with stained fixtures and the 30+ year old faucets have not shown abnormal corrosion.
I change anodes in water heaters every 5 years and there's always plenty left on the anode. I have not had the storage tank side heater long enough to change an anode since they've all failed in less than 4 years time.
I have not had the well water tested for ph but intend to do so.
Plumbing is polybutylene piping.
Heaters have all been AO Smith brand.

My question is why are these tanks failing so fast?
One though I had was that it could be because the storage water heater tank is not powered so it's not grounded? That's the only thing I can think of that's different between the two. Or is it just bad luck?

 

[MACPLUMB]

Have you talked to A.O. Smith about your problem ?

 

[Sponsor]

 

[WorthFlorida]

Have the water tested for PH levels. I see that it is in your comments. Any idea where the tanks leak from? Usually near the welts.

This might be something look into by Rheem. They are under commerical and I have a feeling they are expensive but it may save the day. The smallest tank is 75 gallon.

• Seamless, blow-molded, polybutene tank - impervious to rust and corrosion

https://www.rheem.com/product/marathon-eclipse-light-duty-meld105-tb

 

[Don H]

Have you talked to A.O. Smith about your problem ?

I did not, the tank was replaced under warranty, I had to pay labor. Installer said that AO Smith gave him a hard time about covering it.

 

[Don H]

Have the water tested for PH levels. I see that it is in your comments. Any idea where the tanks leak from? Usually near the welts.

This might be something look into by Rheem. They are under commerical and I have a feeling they are expensive but it may save the day. The smallest tank is 75 gallon.

• Seamless, blow-molded, polybutene tank - impervious to rust and corrosion

https://www.rheem.com/product/marathon-eclipse-light-duty-meld105-tb

Tank appeared to be leaking around the lower element.
I see Rheem makes a 50 gallon poly tank, might have to look into that.

 

[Don H]

So does anyone think that grounding the tank would help?

 

[WorthFlorida]

At the top electrical connection there should be a ground (green wire) tied to the tank.

I found this article that mentions bonding between the hot and cold pipes, but only if it's all copper pipe.

 

[Don H]

Supply is all polybutylene.
Bonding hot and cold copper lines ensures that there is a good group through the buried house supply line.
I installed a water heater in my parent's house and the previous one had a ground wire clamped between the copper two pipes. I reinstalled the same way and added an expansion tank.

 

[Reach4]

I have not had the well water tested for ph but intend to do so.

While you can test pH with narrow range test strips, I would go with an inexpensive pH meter. Those are often sold with packets of the buffer salts to make the necessary buffer solutions. You will always calibrate with the appropriate buffer solution each time, adjusting the reading on the pH meter with a small screwdriver.

The buffer is prepared by adding one packet to an amount of distilled water-- usually 250 ml. Start saving a couple of glass jars with lids

 

[Fitter30]

I'd pull the anode rod for inspection

 

[Don H]

The failed water heater is gone so I can't inspect the anode but the other water heater (the one with power, not the storage one) had the anode replaced after 4 years and it still had a lot left on it.

What would be an acceptable range of ph for well water?

 

[Reach4]

What would be an acceptable range of ph for well water?

No hard limit, but if citing a number, 6.5 is a commonly named point. Corrosivity includes pH among other factors. There are two common corrosivity numbers used. There is a balance point, and one side is on the corrosive side, and the other side is the tendency to leave mineral deposits. But I would start with pH, although a lab test makes sense, especially if your drinking water comes from the well.

Corrosivity can be addressed in more than one way.