If you are like most designers or installers, I would wager that you have never read the installation manual for the piece of equipment that you design or install. And if you do not, you may be held responsible for any omissions recommended in that manual but not implemented.
I was performing research for an upcoming boiler safety class and saw an article about a deadly pool heater in a North Carolina hotel. Due to a malfunction in the pool heater, three people lost their lives. In recent years, several hotel accidents from carbon monoxide poisoning have resulted in fatalities. Carbon monoxide poisoning results in about 50,000 visits to hospitals each year. And each week you hear stories about carbon monoxide accidents.