Upon arrival shut power and gas off to the unit. Took pictures of everything so I can make sure everything is back together for the customer. Pulled old heat exchanger out and put new in place. Made sure everything was tight and no issues. Once all back together tested it and showed customer. I had glued secondary drain line but customer did not want it glued. Pulled it apart so he could clean it at any time so it may leak. Showed customer unit and explained some of the trim parts are dented from having to be raised to get the heat exchanger out. System is working properly and explained the first could times it may smoke and a detector may go off but everything is sealed properly. Customer is happy at this time of service.