Hot water heater not heating

If the water heater is electric; BE SURE AND TURN OFF THE CIRCUIT BREAKER TO THE WATER HEATER, DOUBLE CHECK THE VOLTAGE AT THE WATER HEATER WITH A MULTIMETER BEFORE DOING ANYTHING ELSE!

Here's a good video on how to test the heating elements.


To check the reset button.


To check the thermostat.

take off both front doors on heater,one of them will have a red reset button,press it,it should heat now,if it happens again,you will need new elements

http://waterheatertimer.org/How-to-replace-water-heater-element.html

Gene

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

Call Rheem
Rheem does not post service manuals
Rheem heat pump is same-similar to GE heat pump
http://waterheatertimer.org/Review-GE-Heat-Pump-water-heater.html
http://waterheatertimer.org/GE-heat-pump-manuals-by-date.html

Gene

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

Before calling service technician, copy following link for troubleshoot resources:
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

C4 can range from failed PC Board to lime build-up inside heat exchanger
Error 15 is 'heat exchanger is too hot', clogged heat exchanger, restriction in cold water inlet, temperature set point too high.
If you recently changed temperature setting, then that might be cause.
Tankless require monthy-to-yearly maintenance to avoid common error codes.
Delime tankless and clean water filter, keep temperature low.
Never install tankless water heater is best way to avoid complications of expensive water heater that is maintenance heavy, hard to diagnose, expensive to fix, etc.
Never expose tankless to more than 11 grains hard water.
http://waterheatertimer.org/pdf/Rheem-CondensingTankless-maintenance-2012.pdf
http://waterheatertimer.org/pdf/Rheem-De-lime-tankless.pdf

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

Ordinary tank-type electric water heaters are fully repairable by homeowner.

A) Basic info on Rheem
Rheem electric water heater website:
http://www.rheem.com/products/tank_water_heaters/electric_water_heaters/
Find age of Rheem: look 2nd and 3rd digit of serial number, for example 06 is 2006

B) Water heater has some hot water.
That says certain things: upper element is working, water heater electricity is working, reset button is not tripped, and heater is not experiencing run-away overheating event.
http://waterheatertimer.org/How-it-works.html

C) That leaves 4 suspects that cause lower amount of hot water.

1) TP valve is running hot water out of tank -or- leaking faucet is running hot water out of tank.
Check for leaks
http://waterheatertimer.org/How-to-replace-TP-valve.html

2) Lower element is burned out.
Test lower element using inexpensive multi-meter from Home Depot.
http://waterheatertimer.org/How-to-test-water-heater-element.html
Replace element with same wattage shown on label, and clean out sediment:
http://waterheatertimer.org/How-to-clean-sediment-out-of-electric-water-heater.html
http://waterheatertimer.org/Clean-sediment-out-of-water-heater.html

2) Upper or lower thermostat is bad.
Replace both thermostats for about $25.
http://waterheatertimer.org/How-to-replace-thermostat-on-electric-water-heater.html

3) Burned or shorted wire located between upper and lower sections of tank.
Turn off power. Open covers on side of tank. Remove insulation. Inspect parts for signs of high heat and burning. Especially check lower element. Tighten any loose wires. Replace part that shows signs of burning.
Put insulation and cover back over thermostats so cooler outside temperature doesn't cause thermostat to misread tank temperature.
http://waterheatertimer.org/How-to-troubleshoot-electric-problems-with-water-heater.html

Add a comment for more free help.
Also take advantage of fixya phone service.
For a price, expert speaks with you over phone while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

Replace the inlet and outlet pipe connections. One or both of them is blocked with rust and/or debris.

You probably have a bad heating element. Probably the upper element.

Is the water heater in a basement or an area thats cold? A water heater jacket may help.

If not ,try setting the heat up a little higher on it until you have more then a 5 min hot shower.

May pay you to get a 100 gallon heater.

try setting the bottom 10 degrees hoter than the top could be in short cycle (thatis the bottom calls for heat on the bottom element and set too close so goes back to top and cycles off