I've been trying to figure out issues with my home electric hot water heater the last week. Thought there might be guys in here we could offer some advice. I'll try give a quick run down...
A few weeks ago hot water wasn't lasting long.
Pulled the covers off and saw the lower thermostat was burned out. The T4 wire that connects the upper and lower thermostats was corroded and there wasn't enough wire remaining to connect a new lower thermostat, so I ran new wire solid wire the same size.
Water got super hot and tripped the upper safety switch. With a multi meter I tested thermostats and heating elements. All tested fine. I went ahead and replaced the upper thermostat anyway, as I read that it could test good but could have sticking contacts that are not shutting off.
Water still too hot. Even by turning the thermostats down all the way, water continues to get too hot. Tank has been drained several times and is clear of sediment. I have not replaced elements but they test at the same OHMS as the new ones I have. There are no shorts from element to tank. Also no gap between the thermostats and tank (the insulation and cover press it up to the tank firmly)
I've just been letting it heat at night and then shutting breaker off during the day to prevent the safety switch from tripping.
Sure would appreciate any help to figure this out and not have to buy a new tank.....there are only a few parts to the whole set up....seems it should be able to be sorted out.
Do you have a meter that can test current? Are you sure the temp sensors on the thermostats are making proper contact with the tank?
First question, how old is it? Model would be helpful too.
It was installed in 2012. So I do know that its old....I have a water softener and tank drains clean. It's a 80 gallon reliance tank that is set up just like the diagram above.
Thermostats do sit snug against the tank.
Don't have a clamp meter but I could borrow one from work today.
It’s ready for replacement in my opinion. Tanks last 10-15 years these days before they literally fail/leak. I have about 1200 under my belt as a service plumber. I’d hate to tell you to repair and spend the time/money only for it to leak in your home.
The corrosion on the wires is very telling. In a dry conditioned space, why would it corrode? A lot of times the tank develops a weak spot where the water barely leeches out at first. They can leak for months before it gets bad enough to show.
If the concern is replacing with another 80 gal, we usually replace with a 50 and thermostatic mixing valve or “tank booster”. They work well and save upfront costs. Let me know if you want more info or additional help.
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If you’ve already replaced the lower stat then the problem is the upper stat.
I've replaced both.
The original upper tested fine but I replaced it anyway.
I get the lifespan....but still want to wrap my head around what is actually failing here to cause the overheating. When I mentioned corrosion on the wire, it was more melted/burned. I'll show a picture. But I did replace that wire, as there wasn't enough to connect to the terminal on the new lower thermostat.
Thanks for the advice, the 80 gallon doesn't seem to be a common size these days.
Like you said, they are simple in design. I’ve had elements test good that ended up being the problem. Tstats and elements I always replace together. Hard to zero in without being on site, there’s always more information to be found.
That sounds more like a loose connection with the wire being burned. What happens on a loose connection is that it basically starts to ark , get hot a burn the wire in half.
Are you disconnecting the wires to the element when testing? Are you testing for a ground fault?
Yes I am disconnecting the wires and getting 13 ohms…same as I get on the new elements I happened to have.
I’ve disconnected the wires 3 different times to check for a ground fault and do not have one.
I can’t tell you how many times an element has given a false reading when I check. I would suggest replacing them at the same time as the tstats. Sounds like a ground fault or a stuck tstat. Remember, there isn’t much to these.
I’ve also had new tstats be bad. I’ve had probably 2 dozen brand new water heaters leak after filled too. Think about how many of these get produced, it’s cheap stuff.
Ive been on the phone with A.O. Smith in the past.....I explain my situation like yourself , Dead Air , guy wont even talk to me anymore ...Replace the Unit. , I put a new this and that in and got a few more hot showers out of her...She's Dead. I drain my electric every Nov. And fill her back up in April , even that doesnt get you 10 years lately these days.. lol the A.O. Smith guy .... I put a Rheem in from Home depot ( Plastic drain valve yuch )
Good Luck !
Had to replace a stat once. Had to replace it again a week later. Lots of new junk on shelves these days, it seems.
I ain't no plumber but I am a cheap bastard. Is it possible to isolate one of the elements and just use the other? Then swap. If one of the elements is causing your problem you'd know which one. That's all I got...it's free so not worth much.
There are kits at lowes and other places that have the elements and the thermostats in them that cost around $30 at most. Just start over and change everything that comes in a kit together. If it lasted a year, you would be ahead from the ridiculous prices they have on new tanks.
Ahead is subjective. He could buy another year and that tank might only need another year to fail and leak. I see it everyday!
Like this idea
Pit Row
But is it a "hot water heater" or a just a "water heater"
🤣🤣🤣🤣
Sorry but as this was just in the concrete thread, I had to.
The elements alternate between upper and lower, they don’t heat at the same time. I’ve never done it, but you should be able to disconnect the lower and have the upper still work, but not the other way around. Don’t do it though. Danger.
If it's heating too much, it would have to be a stat - wouldn't it? I am not seeing how a wonky element could cause that. If the stats are working right, the elements wouldn't see the juice.
It can still happen if the element splits and contacts the tank where it screws in. At that point the ECO on the upper tstat is supposed to trip at 170ish. BUT if the tstat isn't working right, it may not trip. I think this condition is fairly uncommon but can still happen. I don't know if I've truly encountered it but I've seen plenty of split elements.
Just replace the water heater. They’re made cheaply and, to get at least ten years out of one, you came out on top these days.
Peace of mind and, elimination of headaches? Priceless.
Coming from a plumber.
Ours lasted 15 years and out of paranoia we went ahead and replaced it before there were leaking issues.
They do make a poly tank model (Rheem Marathon) and a stainless model (HTP). I've installed several of the stainless type but no real experience with the poly ones.
If you changed both thermostats and both elements,wow that's weird you have the same issue. I have replaced like 10 over 15 years. I suggest time to replace,I would do it for free but I live in the Midwest. It's a fun and easy job. The least I can do for a fellow MX Dude.
Shoot I just realized he’s a few hours from me! I’m happy to offer up some help as well.
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