I did edit your question because I wasn't sure if you're asking about anything or just stating some facts. So, I'm answering this edited one. Please correct it if I'm wrong.
The answer is actually in my post "where to install CO detectors" . You didn't specify if your appliances rely on fossil fuels but if they use fuels such as gas or oil, and if the air ducts run from those roof mounted appliances into your house / apartment, than you do need to have Carbon Monoxide detector(s) installed inside your property.
Just in case there is a problem, a bridge between the firebox and the heat exchanger, the circulating air inside the system and your home could become contaminated with carbon monoxide. Just click on "comment" below if you have further questions (it might ask you for your log in info).