Have a p1 flashing on the remote control and no hot water. I have tried shutting the water and power off and still a p1 flashing on the control unit.

Just clean shower head and faucet with CLR solution to increase water flow. p1 means water flow is restricted. Same thing happen to me.

P1 is reportedly defective check valve that can cause water flow to decrease, and tankless not heat water smoothly. But can also be other causes, or combination of causes. Call service technician, contact Rheem, or replace check valve and see if problem solves. Then add a comment with solution so others can benefit from your experience.

Open following link for Rheem/Paloma/Richmond/Ruud tankless troubleshoot resources including error codes, self help, manuals, parts links, tips, and contact information.
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

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