Rheem CL Code

SOURCE: No hot water from tankless water heater. Bliniking Readout

http://www.rheemtankless.com/content/tankless/rheem/help.shtml

This is there website.Above.
Use the live chat to ask them, the code you listed does not seem to correspond to there code list, the only code that does is code 76,
which is a problem with the remote control not talking to the unit.
So your best bet is to tell them the error.

SOURCE: rheem tankless water heater wont lite

the system was not sized properly, you need to have a 3/4 gas line to the unit for the volume of gas it needs, the tankless water heaters need to have every bit of gas that is says, it sounds like who ever installed di not make sure you had enough gas comming in the house, you might have to either have a new meter installed or run the gas lind directly from the meter to the water heater and cap off the gas line thats there

SOURCE: I am getting error code AO and the temperature

its most likely diplaying a code... is it code 21? that usually will follow ao. first make sure the door is securely on, if not make sure it contacts the switch

SOURCE: what is trouble code C8 on a rheem tankless water

c8 is a cycle not a code... the code comes up after it, may look like a temperature... 2 digiti numbetr

SOURCE: Can't find manual & have a C7 error code.

need to contact rheem what you can do until then is remove the control wire it will run until parts ship out