Why not use the natural gas wall-hung boiler?

This is for safety reasons. Must we use natural gas wall-hung boiler for indoor heating? Burning natural gas indoors is very likely to lead to insufficient combustion, and the carbon monoxide formed is highly toxic. You see, the gas water heater is not allowed to be installed directly in the bathroom, but installed on the outer wall and then comes in through the water pipe. Carbon monoxide is colorless and tasteless, and its red blood cell binding force is 200 times that of oxygen. After inhaling carbon monoxide, people don't feel anything at first, but it's too late to feel it. Generally speaking, a small amount of hydrogen sulfide is added to natural gas. Once natural gas leaks, people will smell it and be vigilant. So change the heating mode. It is very dangerous to burn natural gas indoors at night.