The Navien technician hung up on me when I asked him a question about the problem I am having with my Navian CH180. I have had three service people here, spent over $1000.00 and still have the same problem. The technician told me that he couldn't talk to me because I am not the licensed contractor, then hung up on me. Don't waste your money on this company and their products. User's recommendation: Don't waste your money on this company and their products.