It was working fine some days ago, then we started getting cold water. I check the water heater power with a multimeter and am getting NO volts from the top two screws. Even checking the wires I'm getting 0 volts.

If I check the wires from the breaker, they show I have volts. It's only as soon as I connect it up to the water heater do I lose voltage. Please somebody explain this. I've replaced the thermostat hoping that would fix it, but it hasn't.