- This topic has 7 replies, 1 voice, and was last updated 14 years, 6 months ago by .
- Posts
We bought our home in May and our hot water has always been cool enough so with all of the hot water on and no cold on my kids wouldn’t get burned. Suddenly last night I turned the hot water on to wash my hands and within about 2 seconds the water was SO hot it scalded me. What would cause this? What do I need to do now?
thanks!
Kym
Hello: Gas heater and kids playing with thermostat? Or, more likely, electric heater and thermostat stuck “on”. Get it looked at right away. Also, the relief valve should probably be replaced. Home warranty? 😉
Yours, Larry
If the relief valve works, maybe. If not, don’t wait. Go to Safety under Preventive Maintenance to find out how to test it.
Randy Schuyler
I’ll add that you could limp by until Tuesday by turning the power to the heater on only 30 or 40 minutes before you’re going to use it and then back off. Leaving it on is potentially quite dangerous, particularly if the relief valve is stuck 😯
Yours, Larry
Kym,
A thermostat could be stuck closed. The top thermostat has a bimetal thermal switch (electrical cut out) which is designed to open on high temperature in the event that the thermostat sticks closed. This switch (with red button) must be manually reset (pushed in). Once it trips, no power is supplied to the elements.
It is also possible that one element could develope a crack exposing the element internals carrying electricity to the water. In this case, the thermostat may open, but the thermostat only opens one leg of the 240 volt circuit. This leaves one leg (120 volts) supplying power to the element which if cracked will continue to heat water though at a reduced rate. The thermal switch should protect against this if the water gets hot enough and the switch is operating properly. An ohm meter may not detect a cracked element. An ammter will show the continued current flow with the thermostat open.
A cracked element will probably not last long before burning open. But it may continue to leak electricity (and heat) into the water.
David
I think my friend’s got the same problem:
I was visiting him Sunday night and he noticed the electric water heater (located in the attic directly above his bathroom) was making an odd noise: it sounded like a teakettle just beginning to boil — rattling sound like steam bubbles and a faint whistling. I ran some hot water and it was VERY hot. I switched off the breaker right away.
He’s switched it on briefly since then, when he had to shower or run laundry/dishwasher, etc. – it heats up hotter than before, and very quickly, but the rattling sound indicates it’s running non-stop.
So… my guess is: one of the heating elements has cracked, and the sound we’re hearing is an exposed electric wire coming in contact with water and boiling it rapidly. Sound reasonable?
Is it a DIY repair? I know I helped someone replace an element once a long time ago, just don’t remember the details. My friend bought the place just over a year ago, and the heater was new then, but had been wired up wrong and the seller had to have an electrician reconnect it — so maybe the installers did a sloppy/rough job putting it in.
Thanks.
The noise could merely be sediment noise. That has been known to frighten the daylights out of people. The very hot water may be due to a bad thermostat or element. But in any case, as in the original post, this is something you should fix or have fixed immediately.
Electric heaters are somewhat more prone to blow up than gas heaters. And by blow up, I don’t mean break open. I mean blast through the roof like a rocket.
You can find a walk-through on testing elements and thermostats under Tanklets at Electric water heater issues. If all that is Greek to you, contact a professional. Electrocuting yourself will get you just as dead as your tank exploding. Probably deader:(.
Randy Schuyler
- You must be logged in to reply to this topic.