“I appreciate the straightforward tech who came out. We were to submit this estimate to our warranty and then the Navien water heater “sounds” abruptly stopped. We had 5 companies out to diagnose/repair but this tech explained it best and was not aggressive. He said call when we get the approval. Then the sounds stopped. I called the tech and he explained that it could have cleared itself from whatever was blocking it. He felt we should wait to see if it even returns. How honest was that?!”