All of a sudden we have Hot water upstairs but downstairs with plenty of water flow, the water is only warm?

Question

THis problem occured after shutting off the house water supply for a few hours. The hot water heater is less than a year old and is also upstairs.

Answer 1

If it's electric and has 2 elements one of them could be burned out. Any time you shut water off and you have electric hot water, the elements will fry if you don't turn off the power. Elements must be immersed at all times. I would bet it's the top element. Shut off the power, Drain the water heater, the elements usually screw off with a large socket, take it to the supply house and make sure it's the same rating. Be sure that the water heater is completely filled before turning the power back on. Run all the faucets first.

Answer 2

You could have air in the lines which wil keep the water from circulating. Open up the faucet that is farthest away from the hot water heater and let it run. This should cure your problem