The hot water in my facets just starting getting VERY hot - 175 degrees. Has the thermostats gone bad? Both thermostats are set at 140.

Hi Taterbug:

It certainly sounds like it one of them has gone bad. Soon enough, I suspect that the relief valve may begin to leak/drip (as a result of the increased pressure mostly) and/or the upper thermostat will TRIP and need to have its red reset button pressed for you to have hot water. In other words, one of the thermostats is gone.

If you have a typical residential electric water heater it will have two thermostats. Here, I would have you go out to home depot and purchase a UNIVERSAL FIT upper thermostat and a lower thermostat... very cheap to purchase (probably like $10.00 per thermostat).

The trick is to just replace both thermostats because it's almost impossible to tell which thermostat is defective. In terms of your time, in fact, it only makes sense to make the one trip to a home supplier, purchase both thermostats and be done with this once and for all.

Replace one thermostat at a time so you don't confuse the wiring... ;) See image below for a wiring diagram of most double element (left picture) and single element (right picture) water heaters.

Let us know how you make out...

MARK