How water in home is suddenly VERY hot

[Black Adder]

Sounds like the thermostat on the water heater needs replacement, it is not shutting down the elements when it is reaching temperature. I would say with a 20 year old water heater you are definetly on borrowed time. Don't waste the money on fixing it, put it towards a new heater

[Speedy Jim]

Besides thermostat problems, a failed element can cause overheating. If the element shorts to the (grounded) sheath internally, high currents can flow which the thermostat cannot interrupt.

With the power turned off, take the wires off the element terminals and use Ohmmeter to check from each terminal to ground. A good element will read greater than ~10,000 Ohms to ground.

Jim

[wekiva]

We moved into a new-used home about a year ago. 6 months ago our water no longer got very hot. We had a plumber come out and install a new element in our heater. (I believe there are 2 and he replaced 1). 2 days ago our hot water got VERY hot. It will cause a burn if you hold hand under it now. Is this indicative of a failing element? The hot water heater is probably 20 years old...probably time for new one? Or should we check on replacing the other element?

[barry]

I've seen it stated many times by those apparently expert, certainly more so than I, that with electric heaters, the tank can last waaaaay longer than the electricals.

Ask around locally as to how long heaters normally last with your water chemistry. Ask the plumber how the tank innards looked when he pulled the element.

What I'd do:

1) get a replacement anode rod, pull the existing one, and replace. 2) ditto with heating elements and t-stat. You may need wrench to fit element. And proper sealant. Lotsa supply houses all over.

Sediment cleaning is good, too.

That might buy you 10 years more. If you want better insulation, have no problem financing it now, and have suspicions about heater from above, go for a new one. And ... much better yet: gas. Price/BTU typically 1/4 of electrical power.

HTH, J