Hot Water Heater Issue

[phisigbrotha]

Noticed last week my cold water inlet pipe is damp and has corrosion . It starts after the 3/4" tee fitting that goes to the expansion tank.

Here is the hot water side.

Copper flex pipe coming from the wall connected to copper pipe then connected to what looks like a 3/4 brass tee then to maybe a stainless pipe into the AO Smith gas water heater.

I can fix it but I'm concerned with the amount in corrosion sitting on the tank inlet. House is just over two years old and I don't think this is covered under the MFG warranty anymore. Suggestions/thoughts?

 

[theoldwizard1]

Aren't dielectric unions between steel and brass/copper code ?

 

[ishiboo]

Noticed last week my cold water inlet pipe is damp and has corrosion . It starts after the 3/4" tee fitting that goes to the expansion tank.

Here is the hot water side.

Copper flex pipe coming from the wall connected to copper pipe then connected to what looks like a 3/4 brass tee then to maybe a stainless pipe into the AO Smith gas water heater.

I can fix it but I'm concerned with the amount in corrosion sitting on the tank inlet. House is just over two years old and I don't think this is covered under the MFG warranty anymore. Suggestions/thoughts?

The water inlet does not appear to be code, I believe you'll likely need bronze tee if the code doesn't spec a ****** of a certain length... some places do allow brass, and you can see where the problem comes up. You'll need a dielectric between the copper piping and the galvanized.

On the hot water side and the top of the cold water side, the copper flex line with brass nut has a plastic or rubber gasket inside which separates the two.

 

[Frank The Plumber]

This is a power vented heater. The Motor assembly is grounded to the tank casing body. Thus, when it fires up and the fan motor runs the tank body is grounding the current back through the cold water piping. Causing electrolysis.

Some things to check.
Make certain that the power source for the cord set is properly grounded at or within the outlet. The ground really should be going back through the power cord set. For some reason the tank is becoming energized and passing it through to the ground on the service through the cold water pipe.

To correct the damage I would: remove the dielectric ****** from the tank top, replace with a Male iron pipe dielectric union, put a male iron pipe adaptor into the brass tee.

Even though you see that the manufacturer has used dielectric *******, a proper installation will always consist of dielectric unions in addition to thee *******, the manufacturers really only install the ******* to get the poor tanks to last at all when ding a lings don't use anything to stop the processes that rot the weld ******* on the tank tops.

The real problem lies in the outlet box supplying power to this unit. In most cases I find that this is caused by a homeowner rated non grounded power cord being used and the ground tang either not being engaged or just snapped off completely.

BTW, if the power cord has had the ground tang removed, the warranty is most likely void.

 

[phisigbrotha]

Thanks Frank for the reply. It looks like the tank has a dedicated outlet and the three prong cord is intact. Im considering talking to the homebuilder warranty before tackling this myself since I don't think this will be covered by the tank's warranty.

Would you say the builder should have done things differently when installing the unit? IE adding the union from the start. Also is the hot water side susceptible to this same problem?

 

[mgilde13]

I'm just trying to figure out why you're trying to heat hot water?

 

[phisigbrotha]

I'm just trying to figure out why you're trying to heat hot water?

Its 105 here still so the "cold" water is actually hot.

 

[rburke65]

Let it go mgilde13. It's a tank full of hot water. People don't care.

 

[clkimmel]

I'm just trying to figure out why you're trying to heat hot water?

I knew this was comming

 

[Zeke]

He's re-heating the hot water. There, that settles it forever.

 

[cashishift]

that can all be re-done in copper.

No reason you should have that brass in there.

 

[mgilde13]

Let it go mgilde13. It's a tank full of hot water. People don't care.

Wow! Tough crowd in here.

 

[Frank The Plumber]

Technically it should not be happening on the cold side as those are dielectric *******

That is why I suspect that the ground is compromised,although these heaters tend to be a little sensitive to faulty grounding. Is the control valve signaling anything specific. You should have a read sheet attached in the jacket. Generally most units show no lights under proper conditions.

Keep in mind, just because the ground prong has a place to stick into, does not mean you have a happy proper ground.

How old is this? If you can't tell give the serial #. It's in there.

 

[MrMark]

I doubt there is any current running through the water tank and cold water pipe. That would be highly irregular and dangerous. There shouldn't be anything on that ground at all. The ground is not what you think Frank. It is just a safety mechanism should the hot short to the case so that short can open the breaker and be cleared. The return current goes back on the neutral just like every other AC device.

I don't understand this setup though. Why the tee is where it is is a mystery.

 

[Frank The Plumber]

The tee is going for a thermal expansion tank, he most likely has an RPZ or device that is locking the service from expansion.

It does not take much current to cause a reaction on zinc coated parts, it's possible that the metals could even react by their natures. Just the act of water flow creates a minor current.

Try taking a ground clamp and running it from the water service to the top of the tank, a screw or something just so the ****** will stop being reactive.

If you broke off the ground tab on one of these heaters I'm fairly certain that I remember that a code comes up and they do not operate, I know they are polarity sensitive too. Smiths especially.

 

[MrMark]

The controls may be able to detect an open ground and that would be a safety issue, but would not affect operation. I have seen that small current you speak of on the cold water pipes from the minerals in the water and water flow.

 

[plumbstupid]

I agree with Frank, I would check the grounds on the WH and the rest of your home. Electricians generally bond the panel ground to the cold water line at the waterheater.

I've been plumbing for a little over 18 years full time and I have never seen or heard of a brass tee causing galvanic corrosion. Brass fittings are used between galvanized fittings (and stainless) to prevent corrosion from disimilar metals.

Copper fittings in direct contact with galvanized fittings will cause corrosion similar to what you have, but I've never seen it react that bad in 3 years.

Do you have a water-softner. I have seen corrosion on fittings in mechanical rooms with softners and high humidity. If the connection between the tee and the ****** was leaking, along with salt from a water softner it could cause your problem.

 

[phisigbrotha]

Hmm where are the threads?? The 5" ****** was replaced with copper.

For peace of mind and a piece of my wallet I had a plumber come out. The ****** could have easily been replaced myself but I was concerned there might have been corrosion in the inlet of the tank.

Thinking it was cross threaded into the tee when the WH was installed. Now I'm kicking my *** for not doing it myself.

 

[bhclark]

I understand...from the looks of it, I would have been afraid it might snap off as well.

Probably mostly cosmetic actually.

Did the plumber find a cause other than electrolysis between the dissimilar metals?

 

[Frank The Plumber]

Huh?

First.
Where the hell are the threads?
This was threaded into the bottom of the brass tee?

Second.
You replaced this 5" long ****** with a piece of copper tubing with a male adapter screwed to it ? So the plumber made a 5" ****** from some copper and 2 male adaptors and put that in and put the brass tee on the line as before?

No dielectrics?

I think the original problem was caused by a persistent leak that reacted to the zinc upon the dielectric ******. An evaporation and minerals salting causing corrosion situation, not a current induced electrolysis situation.

Please show us the install as it sits now. I am curious and want your problem solved for you and not just BS'd. Thanks.

 

[BigAl62]

I'm just trying to figure out why you're trying to heat hot water?

That's my question too! Got to love a smart a$$!

 

[phisigbrotha]

Huh?

First.
Where the hell are the threads?
This was threaded into the bottom of the brass tee?

Second.
You replaced this 5" long ****** with a piece of copper tubing with a male adapter screwed to it ? So the plumber made a 5" ****** from some copper and 2 male adaptors and put that in and put the brass tee on the line as before?

No dielectrics?

I think the original problem was caused by a persistent leak that reacted to the zinc upon the dielectric ******. An evaporation and minerals salting causing corrosion situation, not a current induced electrolysis situation.

Please show us the install as it sits now. I am curious and want your problem solved for you and not just BS'd. Thanks.

Who knows where the threads are now. Plumber said they deteriorated. And yes it was threaded into the brass tee. I'm assuming it was cross threaded originally.

The plumber went to his truck and came back with the copper 5" ******. No adapter. Threaded it onto the tank and into the tee.

There are no dielectrics. The brasscraft flexline claims to have the dielectrics taken care of. I don't know how copper reacts with what I'm assuming is a steel tank though.

I have to call him back out anyways because now the expansion tank that he had to remove has a very small leak.

 

[MrMark]

That's a brass ******. They are copper colored sometimes. Red brass perhaps.

 

[Frank The Plumber]

That is good. That's a red brass ****** as stated, brass with a high copper content. That should last as long as the heater. Over a long time you could get a reaction that breaks down the weldment on the tank but we are talking 15 to 20 years so that should be fine. A dielectric really does no better in my experience, this is usually better.

 

[phisigbrotha]

Thanks guys!