Just curious to see if any here have experience dealing with an error code 90 on a Noritz tankless water heater. Ours has flashed "90" for as long as we have lived in the house (house built in 2016; we are 2nd owners). I never even knew there was an issue with it because even though it was flashing "90" it always put out hot water. Maybe 6 months after moving in was the first time it stopped making hot water. I just turned off then on again and it started heating, even though "90" was still flashing. That's basically how it goes. It will work just for fine for months at a time, then usually a few times over a couple weeks or so I'll have to go down and turn off then on again. Then it'll work for months just fine. After I first realized it was an error code, I did a descaling but that didn't help. I've had a local company listed on the Noritz website come out to look at it 2x. The first time they cleaned it all, sensors and such, but that didn't resolve the issue. 2nd time he came out, he got on the phone with Noritz and walked through all the troubleshooting, venting, gas supply, fan speed etc. All checked out. He finally used a manometer to take some measurements and made a slight adjustment to the gas or whatever. That also did not resolve the issue. That was several months ago and I have not called them back. Still constantly flashes "90" but works like normal 95% of the time and occasionally has to be turned off then on again.
Any ideas what the issues could be? It seems all the typical issues have been explored. I contacted Noritz myself but they told me to just contact a local company for service.
Any ideas what the issues could be? It seems all the typical issues have been explored. I contacted Noritz myself but they told me to just contact a local company for service.
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