I would call Rheem. Get model number and serial number from label on side of tank. Also note identifying information from side of gas control valve.
And also call the installer.
All water heater manufacturer's have bad units. Period. They all do.
Now Rheem may throw you off and tell you to work through the installer. The installer can also contact Rheem while at your location.
If you installed this unit yourself, you may have to go back to the seller.
If you bought the unit online, then Rheem is best source of information about their products.
Rheem does not post service manuals. I think this is an insult to customers.
All water heaters have 1 year parts, tank and labor warranty for original owner and residential installation. Warranty beyond that can cover parts and tank, and may be pro-rated. Rheem warranty information is likewise difficult to find. Check the Rheem website.
Use circuit analyzer and check that you have correct grounding and polarity at 120Volt outlet. Then check if the is continuity between manifold tube under gas control and the ground prong on plug.http://waterheatertimer.org/images/IMG_9146-gas-control-thermo.jpg
Make sure you are not using extension cord.
Surge will knock out digital gas control valves.
Copy following link for troubleshooting by type of gas control, and that might give some information since other companies post service manuals:http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html#intellivent
You can also post question on pro water heater forum, and find a question that EJ answered, then open question, and left click on EJ name to send message. He is their power vent guy. I'm probably not suppose to say that at fixya, but the customer comes first, and you have a water heater problem.http://www.thetankatwaterheaterrescue.com/forums/forum3/