It looks like the dog did a pretty good job on the door. Since the door is painted, you could sand the area down with some 150 grit sand paper. After it is sanded then you can apply some High performa ... read more
There is minimal maintenance to keep the water heater running good as new. Here is a quick link to some helpful steps http://www.wikihow.com/Maintain-a-Tankless-Water-Heater