All of the sudden, there is no hot water coming into the bathtub. The error code flashing is 12. I believe that is for a fuel sensor? Is that something common to go bad? Expensive? We can't find a dealer near that does repairs, so it is something we can order and install DIY? While researching this topic, I read that hard water isn't good for our tankless. Our softner quit about a year ago and we didn't replace it. Could that have anything to do with the error? (we have a sand-point shallow well)
The kitchen sink water did get fairly warm today. It has always had low water pressure compared to the bathtub. The heater didn't "blink" error code with that, but does when we run the tub. Any thoughts?