Plumbing Questions? Ask a Plumber and Get Answers ASAP.
Hi my name is ***** ***** I have been in the plumbing field for 20 years. I will be glad to help you today. If this is a Rinnai tankless water heater and not a Rinnai space heater, was it working flawlessly before the power outage? What fuel type are you using? Was the fuel supply turned off for any reason?
Is the tank full? Is there a pump on the fuel tank?
When the water heater attempts to fire, do you see any flame at all through the viewing window or is there never a flame at all?
Yes. The troubleshooting will differ depending on whether there is a flame or not. This cannot be determined without observing what happens during an ignition attempt. The code is the same whether there is a flame or not but the troubleshooting is different. Will you observe whether there is a flame at all during an ignition attempt?
Code 12 is a flame failure. There are two kinds of flame failure. One is when there is a flame then it goes out and the other is when there is never a flame. I wish it was as simple as "push the green button" but it is not. The problem must be diagnosed before there is any course of action.