Last night was the first night of really cold weather and it is still cold in the morning when Bob gets a call from the dispatcher that a customer has a carbon monoxide (CO) detector alarm that is sounding off. Bob tells the dispatcher to give him the customer's phone number and he calls the customer on his cell phone and tells the customer to shut off the furnace, get all people out of the house, open the front and back doors, and get out himself. Then he explains that he will be there within 30 minutes.
Bob is driving to the job when Btu Buddy says, "That was good advice you gave the customer. When CO is involved, you can't be too cautious."