The tank will heat water then stop. At times the water is very hot and other times it does not make hot wter at all. I checked the circuit breaker and it was not tripped. What can I do next.

The tank will heat water then stop. At times the water is very hot and other times it does not make hot wter at all. I checked the circuit breaker and it was not tripped. What can I do next.

You didn't say but I assume you have a electric water heater. The first thing I would check is the thermostats. The elements sound like they're doing their job so that just leaves the thermostats.,. Good luck, Tom