I arrived at the house and walked inside to survey the situation. The natural gas forced-air furnace was running full blast, the doors and windows were open, and the smoke detector was in full bloom, ringing like there was a 12-alarm fire. The brother and wife thanked me profusely for coming out at that hour and asked if by any chance I had some aspirin? “Every member of our family has a splitting headache.” “No, I’m sorry I don’t,” I said, “but we can look around for some after I take care of our little noisemaker.” I went out to the truck to retrieve the ladder and noticed my eyes were slightly tearing and burning. I placed the ladder, ascended to the ceiling, and to my surprise it was not the smoke device, it was the carbon monoxide detector that was ringing. “Everybody grab their coats and slippers and get out of the house,” I shouted. I scaled down ladder and shooed everyone outside.
The reason they had headaches was from carbon monoxide exposure. There was only that single CO detector located at the great room ceiling, but I suspect that if there were others located adjacent to the smoke detectors outside all of the sleeping areas those would be sounding as well. Headaches, dizziness, and eye irritation are common symptoms of carbon monoxide exposure.
There were only glowing embers in the fireplace. What was the source of the CO? The CO contamination had to be caused either by the combustion in the water heater or the furnace. Both were fired by natural gas. The kitchen cooking appliances were all electric. Maybe one of the flues was blocked? Maybe a vent flue was damaged and leaking exhaust gases? I immediately shut off the source of natural gas to the home at the gas meter. We continued to let the house ventilate before returning inside to investigate the cause. “Regardless of what the problem is, I think we better find you and your family a hotel for the rest of the night,” I said. “I cannot let you occupy this house until we determine that everything is safe, but that will be tomorrow at the earliest.”
The temperature on that winter night was in the mid-20s. I shut off the water, left the windows slightly cracked, and drained the water heater. On Saturday morning, my heating and plumbing subs joined me at the home to investigate. The flues were intact and operating correctly. The fireplace flue was also fine and found in a fully opened position. It turns out that the high efficiency forced-air furnace had a cracked metal combustion chamber that was allowing combustion gases to circulate within the home as the furnace system was running. Carbon monoxide was being pumped into the house via the heating system.
We removed and replaced the furnace and tested the new unit with a portable carbon monoxide detector carried by the heating subcontractor. The family returned to the home on Saturday and resumed their weekend vacation.
By the way, before the guests returned to occupy the house, we installed battery-operated CO detectors adjacent to every sleeping area. I really have to take my hat off to the building official who encouraged me to use CO detectors. It probably saved the lives of that family and averted a disaster.
Dennis A. Dixon is an author, contractor, and speaker with 21 years experience in the building industry. You can e-mail him at dixven@aol.com.
