The power vent on our Rheem water heater is running much more than it should. We have hot water, but the vent runs for hours after it should, and sometimes comes on when we've not used hot water. What's the problem?

It is posible that you have a hot water leak. Do you have a slab floor house or do you have a crawl space.

When you have no water running anywhere in your house can you still hear water running.

Also you could look at the spinning wheel in your water meter, if it is spinning and nothing is on you may have a leak.

Let me know what you find out.

Lemetellu's thinking that you have a hot water leak and that runs your heater much more then it should. But that's not the complaint is it? You're complaining about the power vent, not the heater itself. Correct? I'm thinking that the thermostat that controls the fan may be at fault. Check it out and let me know. Good luck and thank you for rating my answer. Tom