Ah, but you said you had no water, which is not the same as no hot water! So I, at least, forgive Ej for the joke. Of course, I’m not you… And I have hot water.:cool:
The very first thing to do is turn off the electricity to the heater, remove the top element port, remove the insulation, and hit the reset button. Then put everything back the way you found it and turn the electricity back on. That will probably give you hot water.
If it happens again, though, you can either check out the troubleshooting list for electrics in the Tanklets section of this site or get a plumber out there to see what’s going on.