I would check to ensure that there is a 3" deep drip pan installed with a drain pipe leading outside the building. I would also ensure that the TP relief valve is installed and is connected to piping leading outside the building. Also ensure that the flue is properly vented to the outside. A smoke/fire alarm should be located in the space. It would be a good idea to have smoke/fire alarms in several locations in the house, and at least one CO detector.