일산화탄소는 침실 옆의 온수기에서 역류가 발생하고 있었습니다. 딸은 한동안 숨이 차는 증상을 겪고 있었습니다. 역류는 다락방 환풍기의 동력 팬으로 인해 발생했습니다.

The CO was coming from the water heater next to the bedroom, which was backdrafting. The daughter had been suffering from flulike symptoms for some time. The backdrafting was caused by the powered attic vent fan.