So last week our electric water heater was acting a bit weird, changing the temperature of the hot water for no good reason … specifically, making the hot water hotter than it’s supposed to be.
Then we had NO hot water.
I figured out that the thing had tripped its built-in circuit breaker somehow and reset it, and everything was fine until last night.
Last night when I turned on the hot water at the kitchen sink, it came out of the tap boiling. And I’m not just being dramatic in a “Man, it’s boiling hot in here!”, mind you. It was actually boiling as it came out of the faucet, or at least it was within a few degrees of boiling; it bubbled and fizzed and had steam coming out of the faucet along with the water. The water heater’s temperature setting is at 125, where it has always been.
So what the @#$% could be causing this? Are we in danger of having the water heater explode and kill us all? I shut off power to the thing last night and drew off most of the boiling water before turning it back on, and it’s back to normal now, but … huh?
If the pressure relief valve on your water heater were working properly, I expect you’d see some venting from the top of the, boiling, tank.
Not being a professional plumber, I could be wrong, but a situation like you describe is one of the few circumstances under which I’d go running to a plumber, toot-sweet.
You’re sure you’re not a character in a disaster movie who lives close to a volcano, right?
A little Googling makes it sound to me like the thermostat on your hot water heater isn’t working right.
Disclaimer: I am not a plumber. The closest I’ve come to being one was when I was studying for the physics subject GRE and entertained the idea of dropping out of physics and taking up plumbing, as Einstein supposedly wished he’d done:
Sounds like one of the thermostats is malfunctioning (electric water heaters usually have two elements with a thermostat for each). If the water heater is otherwise in good shape, the thermostat(s) can be replaced.
Not sure what the problem is. What heater problems usualy end up getting solved by just replacing them. In the world of home improvement they are a relitivly cheap expense. If a plumber has to spend more then a few hours getting an old one working you’ve exceded the cost of replacement. How old is it? What is the warrenty?
IANAP, but I have repaired or replaced several dozens of water heaters. As mentioned above, it could be a bad thermostat. It happens and they are relatively inexpensive, $15-$20, and fairly simple to replace. It is entirely possible that the contact points in yours have arced sufficiently that they are sticking nd not opening at the proper temperature. This would explain the extra hot water and the thermal overload trip (what you called an internal circuit breaker). It would be a good time to test your T&P valve to ensure that it will lift properly and reseat. It should open if the temperature goes above 180 °F or the pressure rises to I forget psi. Just raise the little handle and let a gallon or so of water through it. It should be plumbed to a pipe that empties outside. If it is not, catch the water in a bucket.
The other possibility is one I ran across only a few times. The thermostat is okay, it is just being insulated from the water by an unbelievable amount of scale buildup. Usually, scale buildup of this magnitude will cause your heating elements to burn out, but sometimes water heaters in areas of hard water will use a special element, one brand name is Sandhog, that doesn’t burn out when all the water around it boils away. Then the thermostat goes crazy instead.
You can try replacing the thermostat (or thermostats - there is one for each heating element and many heaters have two). Or if you are somewhat handy, you can drain the water heater (turn the power off FIRST), remove the lower element, and check for scale. If it is pretty much full of scale, you’ll probably need a new heater. If not, the thermostat(s) should fix it.
This happened to the water heater in my previous house - the water fluctuated in temperature for a few days, becoming dangerously hot quite suddenly. I went into the basement and found the water heater shooting boiling water out of the pressure relief valve. It was jetting out pretty violently and had pitted the concrete under the water heater. Since the heater was older, I didn’t bother trying to replace the thermostat (I don’t think that I would have felt safe with the thing even if the thermostat was replaced). Running out to Lowe’s, buying the new heater, and installing it took all of three or four hours, and that included some framing work to install earthquake anchor straps to bring things up to code. I kept the old water heater tank and used it as a lawn roller for a while.
Right after moving to our current place, the same dang thing happened, only this time it was in a finished basement, AND the pressure release valve was not completely effective, since the tank was spraying both through and around the valve, indicating a leak. This was a gas heater with brazed copper fittings, so I had a plumber do the replacement installation. The upshot of this is that I now test the pressure release valve on the water heater whenever I change the whole-house water filter or add salt to the water softener.
We haven’t replaced it because the landlord won’t do it and we aren’t allowed to (it’s a compact-but-wide unit that fits in a little closet under the stairs, so it’s extremely expensive, evidently). Fortunately, we’re moving in a week or two anyway.
I tried the pressure release thingy on the top and it seems to be working; it releases steam and/or water directly into a drainage pipe that goes off to an unknown location, perhaps onto the bed of the evil downstairs neighbors.
So now that I see that the pressure valve is okay, I’m less worried, and I think the thermostat on one of the heating elements is messed up. It works again now; the water is at normal temperature. So it’s got to be the thermostat on one of the elements…
Just because you can operate the relief valve manually does not guarantee that it will release by itself when it should. It might, and you might be fine, but it might not. Normally steam and bubbling water coming out the taps is a sign that relief valve is not working properly, as it should have opened already before things get that hot.
And the next time the thermostat doesn’t shut the heater down when it should, the problem may solve itself by blowing the heater out of the house by way of your bedroom.
I spent 9 years working in place that sold these things (and lots of other temperature, pressure, and heating controls) to plumbers and HVAC technicians. We collected stories about the worst installations, most dangerous hacked up fix-it jobs, and the worst accidents that we heard about.
I have seen houses destroyed by water heaters with bad relief valves, literally damaged so badly that it they were not worth fixing, it was cheaper to knock down the rubble and start again. I’ve seen people maimed, burned, and killed.
Believe me, this is not something to take a chance with. Get someone who knows what they’re doing to check it out.
While this is true, the fact that the valve moves freely is a good indication that it will work. Water at 180 - 190 °F will look pretty impressive, but is still inside the limits of the T&P valve.
I mis-remembered this. The specs for a standard T&P valve (Watts 100XL) are 210 °F and 150 psi.
So while it isn’t a good situation and certainly needs to be resolved ASAP, I would not characterize it as dire. As an adult, he should take whatever precautions he deems prudent.
OTOH, a little bit of theatrics to the landlord on your fear of imminent flaming death and the expensive litigation to follow might help get the cheap bastid to get this fixed pronto.
Thanks for this information, Rhubarb. So does that mean it shouldn’t open by itself until the temperature and pressure get up to 210°F and 150psi? I didn’t have a thermometer that could measure the temperature of the water, but how hot would it have to be to boiling to be hissing and spitting as it came out of the faucet? And also, when I filled up a cup, it roiled a little, with bubbles coming up to the top. I assumed it was actually boiling, but it might have just been close.
And incidentally, the lower element has burned out before, and we (the building handyman and I) replaced it, but the tank is so full of scale that the drain was completely clogged, and water would barely drip out. Eventually we did something that blew the scale out from the drain and let water drain for a few minutes until it clogged again. We kept doing that until the tank was empty enough to replace the lower element. So yeah, the tank is EXTREMELY full of sediment; I live in southern Nevada, and the water around here is extremely hard, and the tank is the original that was installed when this building was built, in 1980.
And RJKUgly, thanks for your information too. That’s pretty scary. I had no idea an exploding water heater would do so much damage. I’ll see about getting the landlord to replace it.
Thanks to everybody else who posted, too. I’ve learned a lot.
In my previous post, I erred on the side of caution. I don’t know what kind of equipment your dealing with, how old it is, or if it’s properly installed. Judging by your last post I would stongly recommend that the entire water heater is way past it useful life and needs to be replaced, not just repaired.
It is a good a indication that it should work, no doubt about it, but it isn’t absolute. And even if the relief valve does stick and thermostat lets the temp run away again, chances are it will probably just open a seam and blow out that way. Messy but not necessarily catastrophic.
But sometimes things go badly. I have seen with my own eyes what can happen when things go badly.
If there was actually steam and bubbling water coming out of the taps that sounds like water above boiling, and the relief valve should have opened. So we may have a symptom of a partial current failure. Not for sure, maybe not even probably, but it does bear looking at.
This is a situation where the cost to have it checked is enormously less than the cost of failure. If it were me, I’d get it checked out (actually I’d just replace it myself, but that’s not an option for everyone).
Would I do it tonight? No. Just operate the thing manually for a couple of days (turn it on when you want hot water, turn it off when the water is hot enough, don’t rely on the thermostat) until you can get someone qualified to take a look.
A “standard” water heater usually has two heating elements, upper and lower. One of the heating elements has corroded and will cause exactly the symptoms you describe.
When we first moved into our house, the hot water temp fluctuated radically for a couple days then seemed to “heal.”
My husband when out of town for a month a week after we moved in. One evening a week after he left, the hot water came out boiling.
Our basement was unfinished. The stairs were open on both sides. The only light was a pull chain at the bottom of the stairs. When I went down to turn off the breaker, I noticed that the pipe coming out of the top of the hot water tank was glowing red. Needless to say, I turned the breaker off and called a plumber in the morning.
Over the phone, he guessed it was the thermostat, but it turned out to be one element. He replaced both. It didn’t take long or cost much, and the tank lasted another two years.
When we replaced it, unfortunately, hubby didn’t read the instructions and turned it one befor it was full so he had to replace both elements in the brand new tank.
