Rheem electric water heater 50 gallon, lukewarm water. Water is warm but not hot, where should we look for problem?

http://waterheatertimer.org/How-to-troubleshoot-electric-problems-with-water-heater.html#reset

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Gene
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Rheem 50 gallon Pro52-2 has EF .95, which makes it ordinary 240Volt 4500 watt non-simultaneous electric water heater that produces about 21 gallons hot water per hour, with 67 gallon first hour delivery.
Recommend 80 gallon per hour first hour for oversized bathtub.
http://bostonheatingsupply.com/Rheem/Rheem%20Residential%20Electric/Professional/Rheem_ResidentialElectric_Professional%20Spec%20Sheet.pdf

Maintain electric water heater and it will last indefinitely.
http://waterheatertimer.org/How-to-maintain-water-heater.html
http://waterheatertimer.org/9-ways-to-save-with-water-heater.html

Anode rod is located on top in separate port.
Anode keeps tank from rusting.

Year of Rheem water heater manufacture shows 3rd and 4th digit of serial number.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

It could be element shorted to ground through steel tank, so don't touch tank when breaker is ON.
Or you have undersized 12 gauge wire and 20 amp breaker and the heat has loosened breaker on the busbar. Breaker trips when heat exceeds breaker limit. Jiggle breaker and listen for crackling sound.

To restore hot water now:
Turn off circuit breaker, and open top cover then Push in reset button on top of heater to restore functionality. Put back insulation and factory cover.
To fix water heater: test and replace bad element.
http://waterheatertimer.org/How-to-test-water-heater-element.html
If problems continue
http://waterheatertimer.org/How-to-troubleshoot-electric-problems-with-water-heater.html#trip-breaker
http://waterheatertimer.org/Troubleshoot-household-electricity.html

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Gas unit? if so check pilot --will go from there-if electric check breaker in electric panel

look for a badly connected power line ont he bottom element, or any connection upstream of the power terminals. voltage readings usually drop to that range when you only have one side of the 220v circuit connected.

Check the elements, if you have access to a meter to check them. If they are getting power to elements and you have no hot water.
The elements are not working correctly. I had some elements check out ok till the thermostat's turned on and the elements didn't heat.
Sounds like the elements are bad.

Possible thermostat problem. Are you experienced enough in that area to do some testing. Have a multimeter? If not experienced, don't try it, too dangerous. Call in a service person.

you have a couple things that may cause this. you may have a bad element a bad thermastat a tripped eco (emergency cut off ) or problem with electric suppling heater.if you have no electric backround or training you should call a pro