By Mark Hunt
Special to CONTRACTOR
When Doug and Sarah Haight signed the final papers at their closing, they achieved part of the American dream, owning a home. They moved into the house in Queensbury, N.Y., with their 1-year-old baby boy and began the task of settling in. The home inspectors had checked the house and found everything in good working condition. It was early September and summer was holding on, refusing to give way to fall. The home’s gas-fired, forced-air system was complete with central air conditioning so the house stayed cool on the warm Indian summer days.
Sarah Haight and the baby both had not been feeling well, but she wrote it off as stress from the move and the new environment. She and the baby stayed at home while Doug Haight went to work.
It just so happened that the local utility was in the area upgrading gas meters so that they could be read remotely. A utility serviceman rang the doorbell and introduced himself to Sarah Haight and asked if he could come in and see what types of gas appliances they had. She agreed and showed him to the basement door. It was very fortunate for her that he came.
Recipe for disaster
What he found in the basement was a sure-fire recipe for disaster. The previous owner had replaced the original water heater before he moved out. The problem was that the original water heater was a power-vented unit and he replaced it with an atmospheric-vented unit. He attached the flue pipe from the atmospheric unit to the sidewall termination of the power-vented unit and left it at that. When the serviceman saw this, he shut off the gas to the water heater and locked the gas valve. He told Sarah Haight that he could not leave the water heater in operation and that she needed to get it fixed before he would unlock it. That’s when she called me.
I had known the Haights for a few years, and when Sarah called me I could hear the panic in her voice. I told her we would be right there.
When we got there, we found no traces of CO on the first floor, but the basement had 11 ppm, which is not life threatening to most adults but can be dangerous nonetheless. This was about an hour after the serviceman had shut it off. There it was, an atmospheric water heater vented through the termination of a power-vented water heater.
It was what we also found in the basement that convinced me that the serviceman from the utility had saved the lives of my friends. Not only was the water heater pouring combustion products into the basement, the forced-air system was drawing the combustion products into the ductwork and pumping it throughout the house.
This was due to the return drop being almost completely disconnected from the side of the furnace and a huge hole cut in a panned return bay. Whenever the fan on the forced-air system ran it severely depressurized the basement and all the CO that the water heater was producing was pumped into the house. We replaced the water heater with a power-vented unit and fixed the ductwork.
Stories about carbon monoxide almost always have a quote like this, “A faulty furnace was believed to be the source.” Of course, we never hear why or how it became “faulty.”
As a certified Home Energy Auditor with the New York State Energy Smart program, I get to enter and test many homes. A problem that I find quite often is depressurization of the combustion appliance zone, or CAZ.
Worst-case test
The CAZ is simply the area where combustion appliances are found. When we test a home, and we test all of them, a “worst-case depressurization” of the CAZ is the second test we perform. We do the first test the second we step in the front door. That is an ambient CO test and I have gotten pretty good at sticking my Bacharach Fyrite-Pro combustion analyzer under one arm while shaking a customer’s hand with the other. You never know what you could be walking into.
A worst-case test is pretty simple. Close all the windows and doors in the house. If there happens to be window air conditioners in place, remove them and close the window. If there is a fireplace, make sure that the damper is closed. Then we turn on any appliance or fixture that exhausts air to the outside. This includes clothes dryers, bathroom and kitchen exhaust fans, anything vented to the exterior of the home. We will also run the fan on any air-handling equipment. Leaky return ducting causes depressurization as well.
With everything running we test draft the combustion on any atmospheric appliance. This test is mentioned in most manufacturers installation manuals, but instructions almost never get read much less followed. I would be willing to bet that the graffiti in portable toilets gets read more than instructions.
Another example of CAZ depressurization involved a home where a major kitchen remodel had recently been completed. The homeowners liked to cook, so they had a large gas stove installed complete with a 1,000 cfm exhaust hood. Standing in the kitchen you would never know what happened in the basement every time these folks ran the exhaust hood.
When 1,000 cfm of air was exhausted, air to replace it found its way back in through the biggest hole in the house — the chimney. The air was rushing out the draft hoods on both the gas boiler and the gas water heater along with an unhealthy dose of CO.
Now who would have connected a kitchen remodel with a CO death had one occurred? I can see the headline now, “Faulty boiler kills family.” It certainly would not be, “Properly functioning exhaust hood causes depressurization of combustion appliance zone killing family.”
All this points to one conclusion. When CO is involved, common sense takes a walk. This is despite the fact that carbon monoxide accounts for more than 90% of the accidental poisoning deaths in America.
Currently, no laws require contractors to test for CO, and subsequently they do not. While most manufacturers mention depressurization testing in their installation manuals, most will also agree that those manuals never get read.
In this day and age, the fact that carbon monoxide poisonings rank as No. 1 for accidental poisoning deaths is a black eye for our industry. Granted, not all the CO-related deaths are attributable to heating equipment, but far too many are. It is my contention that any contractor that installs combustion appliances should be required to pass a course on combustion and CO. Contractors should be testing every home they enter and every combustion appliance they encounter.
We are supposed to be the experts, not the fireman, paramedic or emergency medical technician.
Mark Hunt is a Certified Carbon Monoxide analyst, a Tech I home auditor and a Tech II heating specialist in New York state. He is also a principal partner in Comfortable Home Technologies, a contracting firm in Ballston Lake, N.Y. He can be reached at [email protected].