Jacuzzi Water Heaters - Recent Questions, Troubleshooting & Support

My Navien is doing the same thing, and it's 6 days old. The older unit did the same thing as well... I'm guessing it has nothing to do with the unit, and something to do with the line... I'd love to get to the bottom of it as well.. :(

Follow the link, you need to "Descale" the heater. Tankless Water Heater DeScaling How To Flush

If your GFCI is tripping, it could be due to a bad heater element, pump, blower or ozonator. To determine which component is causing the problem, unplug the components one at a time and turn the breaker on. If the breaker does not trip after unplugging the pump, ozonator or blow, you've found the problem and you can now replace that component. If you've unplugged all three components and the breaker still trips, it's likely the heater element. Hiring a technician or replacing the heater is the next best course of action.

The error 11 indicates that the burner did not ignite the incoming gas properly. Make sure that the gas valve is open (at the water heater and the meter/tank, depending on the type of gas). If you have propane, check that the tank isn't empty. Make sure that the water heater is properly grounded. The other causes for the error may require a professional to check them out. Check that the water heater is compatible with your incoming gas. (Propane burners do not work with natural gas and the reverse is true, as well.) Check that the gas pressure available is high enough for the unit. (Tankless water heaters often need larger diameter pipes to bring in the gas than their tanked predecessors.) Check that there is no air in your gas lines. Make sure that the condensation collar was correctly installed on the water heater and that the vent pipe isn't too long. There are some DIP switches that need to be set depending on the installation; make sure that all of these are in the correct positions. Next the burner, the igniter and the solenoid gas valve need to be checked. The wiring for the igniter and the valve need to be checked. The burner cover has to be removed to check if the burners are properly seated. The burner plate has to be removed so that the burner surface can be checked for debris or condensation. The igniter has to be checked to see if it is operational. Finally, the solenoid valve needs to be checked for a short or an open circuit. I hope this helps. Cindy Wells (I've also had to check the end of the vent pipes for blockages - animal nests in the summer or ice in the winter.)

Theres no fix for your problem cause your water heater is fu.k.d up.  Go out and buy you a new one and don't forget the expansion tank.

There is a ground fault somewhere...you need to isolate it with an ohm meter.

If it was only used once it must be perfect. What is wrong?