The Tank › Persistent water heater issues
- March 23, 2009 at 11:19 am #11026
I’m hoping to bounce some ideas around regarding some water heater issues we’ve been having for quite some time now. This might be a longish post, but it seems useful to have the entire history here.
Our house is pretty new; 4-5 years old, so we are talking about new(ish) construction. We have a pair of 50-gallon Bradford White electric water heaters. We are on a well; which provides us with water that is hard, and has iron in it.
To solve those issues, we have both an iron filter and water softener.
We have found that we are losing a water heater about every year. They seem to be on alternating schedules – one will go out (and get replaced), the next year the other one will go out (and get replaced), etc etc.
So, we have had three or four replacements since we built the house. So it is clearly not a fluke or a case of a bad unit.
When the heaters go out, the problem manifests itself in the from of a pinhole leak in the tank. The plumbing contractor does not spend too much time trying to diagnose the problem (despite my insistence) and just swaps a new unit in and hopes for the best. However it is clear that this is not actually fixing anything, and we want to actually solve the problem.
I brought another guy in from another company to take a look at things. He was a pretty smart guy, and knew enough about plumbing, electrical and geothermal (we have a geothermal unit also) to kind of check everything over. This guy did not come up with any ideas, except maybe to have the plumber use dielectric unions. That advice seems off-base to me because the water heaters should have dielectric nipples already.
He briefly considered a water quality problem, but since we do not get any rotten-egg smell in the water, he dismissed that idea.
Now, when we came out (this is a month or so ago), we had a leak in one of the heating elements, so I had the original plumbing contractor out to fix it. He pulled it out to swap it and it seemed (to me) to be highly corroded. At my insistence he pulled out the anode rod. It looked to my eye to be quite corroded for only being a year old. I wish now that I had taken a photo of it.
So that led me back to considering a water issue. I took a sample of our softened water and sent it to a testing lab here in town. The results came back and things mostly looked normal except for some elevated sulfur levels and (what really caught my eye) was an elevated sodium level.
To be specific, the sodium level is 430 mg/L in our water. I have an email in to the lab to get a feel for what the normal range is, but this seems pretty high.
So I started to wonder if our water is over softened and the sodium is eating away at our tanks.
Anyone have any experience here? It could be that the water is being over softened, in which case we can dial it in to the right level, but is there anything else we should do? Will water at the correct level of softness always kill a water heater prematurely? Would using potassium in the softener instead of salt help, or does using potassium create a different set of problems?
Not expecting anyone to give a 100% definitive solution based on my explanation, but we really need to solve this problem – having water heaters go out all the time is no fun at all.March 23, 2009 at 12:42 pm #11027Randy SchuylerKeymaster
The softening is definitely an issue. Softening exchanges salt for mineral hardness and salt increases the conductivity of the water, which speeds up consumption of anodes. Anodes do look like hell when they start to corrode, but the rule of thumb is that you don’t replace them until there is six inches of core wire exposed anywhere on the rod. The softener should be set to 50-100 ppm and the anode should be checked once a year for a couple of years and thereafter as seems best.
Beyond that, you should also check your water pressure, which shouldn’t be more than 80 psi, and you should do the test for thermal expansion described in the Tanklet titled Temperature/Pressure Relief Valves. Tanklets is in the Troubleshooting section of this site.
Randy SchuylerMarch 24, 2009 at 1:21 am #11031Larry WeingartenParticipant
Hello: If you cannot soften less as Randy suggests (and you should do, leaving 50-60 to 100-120 TDS hardness in the water), replace heaters with Marathon units. They are plastic and have no anodes. http://www.nsf.org/consumer/drinking_water/dw_quality.asp?program=WaterTre is a link to some useful info. In looking around, 20 mg/L seems to be the maximum for ingesting, if your diet should be sodium restricted… see link http://www.ocwa.org/o2624.html . If you’re getting blue or green water marks in sinks, copper pipe is dissolving and too high a salt content may play a part. Certainly it’s eating up anodes. I’ve seen anodes down to a bare wire in six months in over-softened water 😯
Yours, LarryMarch 24, 2009 at 9:23 am #11033
Thanks for the responses. I think the plan is pretty clear – make sure the softener is set properly (need to get this dialed in) and then periodic checks/replacement of the anodes going forward. Should be no problem to do this myself once I get my plumbing skills up to snuff.
If/when we need to replace a unit, we can look at getting a different type.
Checking the pressure is a good idea, and not something I’d considered.
HOPEfully this will keep us up and running for the foreseeable future. Thanks again.March 25, 2009 at 2:18 am #11043undee70ssParticipant
Checking the pressure is a good idea, and not something I’d considered.
Get a lazy pointer water pressure gauge and leave it connected overnight. Then you will know for sure what the max pressure is. High water pressure also shortens water heater life.August 6, 2009 at 8:51 am #11829
Short update and another question –
We have dialed back the water softening for now, and no water heater problems so far, so that is good.
However, one thing we aren’t thrilled with is that due to how hard our water is, it still requires a good bit of softening, which of course results in higher sodium levels in the water. I am kind of paranoid about this (maybe justifiably, maybe not)
We are considering using the potassium-based media for the softener instead of the salt.
My primary question is – will switching to potassium cause any change in the premature corrosion that we’ve been seeing in our water heaters? That is, is it the salt the causes this, or the softening process in general? I haven’t been able to find any information about this either way.
Any thoughts on the impact of using salt vs. potassium?August 7, 2009 at 11:12 am #11831Larry WeingartenParticipant
Hello: There is no research that I’ve been able to find on this question. However, it is possible to measure the conductivity of the water and that has a direct impact on how fast anodes are used up. So, whether it’s salt or potassium, check conductivity.
Another thought might be to put a reverse osmosis (RO) unit under the sink to give you drinking/cooking water. That way you get a degree of separation from the softener 😎
Yours, LarryAugust 18, 2009 at 8:50 am #11868
Thanks for the response. We will probably try out the potassium and see how it goes. I’ll get a water test done a few months after we switch and report back the results.
We’ve considered getting a RO filter for drinking/cooking water, and that’s still an option if we stick with sodium-based media in the softener.
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