C4 67 error message, what does this mean - Rheem Paloma Tankless Water Heaters PTG-74PVN Tankless RTG-74PVN

No, there isn't an Error 09, but there is a E19.

https://www.tanklesshotwaterguide.ca/about/rinnai-tankless-error-codes/

https://www.google.com/search?q=Rinnai+E110CN+error+E09

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i think its "child lock" meaning u need to reset it somehow to clear it.

Yo James,

I know nothing of your unit, but I've never let that stop me before??.

Sounds like a sensor is stuck in the "tray full" position and popping an error message based upon what "it" is detecting.

OK, how does the unit know from "full tray" (what ever that means). I'm a big believer in problems being created by dirt, crud and in your case, coffee grounds. Unless the sensor (switch?) itself has failed, I'll bet there is debris fouling the system.

Find the "full tray" (what ever that means ??) sensing mechanism and clean/replace it and I'll bet you will solve the problem.

All the best.

The error is a HIGH LIMIT THERMAL ERROR. That means Calcium buildup has appeared in the unit. It is also called scale. To clear the error you have to power it off. That is done by the circuit breakers. You should descale the unit first though.

is it an electric or gas or oil fired. Er3 means it is not getting up to temperature within the required time. Electrical - element bad. for oil or gas, no ignition or fuel supply.

Open following link for rheem tankless resources, including error codes and typical maintenance.
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

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

Before calling service technician, open following links for Rheem tankless resources including error codes and Rheem chat.
Disconnect wires from remote to see if system stabilizes. Unit will heat to default temperature without remote.

Error codes are considered start-point for troubleshooting.
C8 76 can mean PC board failure.
76 can mean communication failure with remote control
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html
http://waterheatertimer.org/pdf/ErrorcodeTroubleshooting.pdf
http://waterheatertimer.org/pdf/Rheem-error-code-C7-76.pdf

a 16 error code is typically caused by scale formation. I'd recommend performing a descale on the heater.

4 error message, the 4th (last) error code is #13, not enough oxygen.

Check the location of the heater, if it is fine the ODS sensor (actually is a thermal couple) is bad.

1/ check overheat stat 2/ check fan esp the little hose at the fan area for pinhole best of luck