I would first look at the owners manual and or the schematics. You can probably find it on line if you have the model and serial number. I would then call a Rheem dealer or contact the company to see what that error code is. Personally I wouldn't try to fix it myself because it's gas and if you screw up you could blow youself up or burn the house down. That's why I buy electric water heaters and a water softener. I may pay a little more in electric but with the softner to remove the lime, I never have to change an element, only add salt about every 3 months.
Answers & Comments
I would first look at the owners manual and or the schematics. You can probably find it on line if you have the model and serial number. I would then call a Rheem dealer or contact the company to see what that error code is. Personally I wouldn't try to fix it myself because it's gas and if you screw up you could blow youself up or burn the house down. That's why I buy electric water heaters and a water softener. I may pay a little more in electric but with the softner to remove the lime, I never have to change an element, only add salt about every 3 months.