I ASK THE QUESTION that’s in the headline only because I have concerns for you and your loved ones. I didn’t used to test any of our gas-fired appliances for carbon monoxide either. It isn’t required and, besides, why spend time doing something that isn’t required? Right? I mean with all these plug-and-play appliances, who has time to waste testing the flue gas stream on a perfectly good, brand-new, fresh-out-of-the-crate appliance?
Then it happened. I got a call from a good friend for whom I had installed a power burner-fired boiler in his home in the mountains. It seems that the boiler had almost killed him and his sister, who was in town visiting for a month.
This actually happened about six years ago. I installed the burner per the manufacturer’s installation recommendations. All except for the part where it tells you to test the flue gas stream for all the gases typically found in the exhaust stream of a gas-fired boiler. I didn’t have a combustion analyzer, and neither did the company that I worked for at the time.
I didn’t think I needed it because the boiler lit off no problem, the burner “appeared” to be burning cleanly and correctly, and I couldn’t smell anything, like un-burnt fuel. I was as ignorant as a newborn child. That’s a tough admission, but it was true.
Fortunately for me, my friend was a volunteer fireman, and he had recognized the early warning signs of carbon monoxide poisoning and had taken appropriate actions to avoid being permanently injured or, worse yet, killed by this silent, invisible, odorless killer.
He contacted the local building officials afterwards and asked them why they weren’t requiring new homes under construction to have a carbon monoxide alarm installed in the home, at the same time they were enforcing the requirement that smoke detectors be installed. He was told that it is not a requirement of the nationally recognized code that the county had adopted and, if it wasn’t in the code requirements, he couldn’t enforce it. Sad but true.
As soon as I got the call from my friend, I borrowed an analyzer from another friend and immediately went to the jobsite to take corrective action. When I arrived, I found that he and his sister had packed the spaces surrounding the mechanical room door tight with wet paper towels to ensure that the killer gas stayed on the other side of the door. It seems that the gas was backing up from the barometric damper/draft diverter connected to the boiler’s flue gas breaching during a windstorm that had been blowing the night before. This caused the flue gas spillage. The boiler had its own isolated source of outside combustion air piped directly into the burner inlet in the mechanical room, so his drastic corrective actions didn’t compound the situation.
I started the combustion analyzer outside the home to “zero” the instrument before going into the home. When I got inside, enough CO was still in the home to show a residual reading of 15 ppm. Not terribly high, but high enough to take notice. He’d kept windows open all night long in an attempt to air out his home.
When I went into the boiler room, the instrument was showing CO at about 50 ppm. I shut off the gas to the boiler and allowed the blower motor to continue running to help air out the mechanical room. I pulled the orifice out of the burner and verified it to be the proper size for the application. I checked the air shutter adjustments to make sure that they were where they were supposed to be, and they were correct. I reassembled the whole works, drilled a hole in the smoke pipe before the draft regulator and restarted the boiler. When I went to test the flue gas stream for CO, the quantity of CO was so high in the flue gas stream that it immediately caused the flue gas analyzer to shut down and lock up. Not a good sign.
After much tweaking and readjusting, I finally got the boiler to burn cleanly with almost no CO in the flue gas stream. This was an extremely expensive lesson for me, and it could have cost me my friend and his sister’s life. I feel very fortunate that he recognized the symptoms of CO poisoning and took action.
I immediately went out the next day and purchased a flue gas analyzer and began testing every appliance that I came into contact with, including the appliances in my own home.
They have a saying in this business: “If you’re not testing, you’re just guessing, and if you’re just guessing, you could be gambling with someone’s life.”
Tune in next month as we continue to look at this, the nation’s most common form of preventable poisoning, known as the silent killer.
Mark Eatherton is a Denver-based hydronics contractor. He can be reached via e-mail at [email protected] or by phone at 303/778-7772.