Can anyone identify this?

[jla22]

Suddenly have no hot water so pressed the button and the light turned off but only heated the water a little bit. Then the light turns on again. If I keep the button pressed would it heat more water?Thanks in advance for any advice.

 

[JG plumbing]

Your tripping a breaker. Something is wrong.

That being said I don't even know what I'm looking at.

 

[Twowaxhack]

Looks like a way to control the water heater so it’s not only operated by the thermostat.

I believe it’s a manual timer. If the thermostat calls for heat the timer is pushed and the water heater heats until the thermostat is satisfied or the timer expires, then you have to push again.

 

[Jeff Handy]

Yes, maybe a timer to only heat water when electric rates are lower, probably at night.
This only applies if you are signed up for a pricing program like that, through your electricity provider.

 

[House Doc]

Over the years I've installed quite a few timers on electric water heaters. The idea being that normally, mostly when you take your showers, morning or evening, it would be on. They had multiple settings so you could "tune" it to your needs. It had it's followers, as such, and wasn't hurting anybody, so why not. It kept the heater from running all day long to keep the tank at 120 degrees. It would turn on about an hour before you needed the hot shower and off later. The tank would hold enough hot water for small tasks like kitchen/hand washing.
This might be a more modern version of that idea.