Thinking warmth? Think safety first

It seemed we had hardly hit the bunks in the remote, north woods cabin when the commotion made me forget how sick I was suddenly feeling.

In the dimly-lit cabin I watched one of my fishing companions stagger into a kitchen table, bounce off the wall and land on all fours. He crawled out the doorway, leaving the door wide open on a chilly, May night.

And in so doing, he saved our lives.

The open door allowed fresh air in and reduced the build up of carbon monoxide that had made him so nauseated that he wanted badly to get outside, and so dizzy that he almost couldn't make it.

So it was with more than casual interest that I watched Tim Dorry do what he does three or four times a day this time of year.

Dorry is one of three technicians with Kelly's Heating and A/C Inc., New London, who perform furnace inspections.

He inspected the furnace that heats Jim Vossen's home on the edge of New London. Although the home and furnace are only three years old, Vossen is among those who know the value of proper maintenance. He is enrolled in a maintenance program with Kelly's that includes an annual inspection of the furnace.

Each year, an estimated 500 people die in the U.S. due to unintentional carbon monoxide exposure, according to information from the Minnesota Department of Health. The U.S. Consumer Product Safety Commission estimates that 8,000 to 15,000 people each year are treated in hospitals for exposure to this invisible gas.

All types of combustion create carbon monoxide, and the causes of accidental poisoning range from cars left running in attached garages to charcoal grills used in enclosed spaces.

Making sure your furnace is operating properly and venting its gases outdoors is just one step you can take to assure your family's safety from carbon monoxide poisoning -- but it's an important one.

It can save loads of cash too. A properly running furnace uses less fuel, said Dorry.

Having a furnace properly maintained by a qualified technician can also protect warranty rights. Consumers cannot be certain that manufacturers will replace parts when it's apparent that a lack of maintenance is responsible for corrosion or other damage, he noted.

Dorry has been inspecting furnaces since 1998 with Kelly's. He has uncovered his share of problems.

He guesses that the average furnace he inspects is around 15 years old. Most of those he sees are between 10 and 20 years of age, meaning many are approaching their expected life spans and at the point where problems can develop.

Yet it makes no difference whether a furnace is highly-efficient and new or cantankerous and old. Dorry said most of the problems he uncovers are the types of things the average homeowner would never notice. They occur behind the sheet metal panels that cover the working parts of the furnace.

If the burners on a furnace aren't operating properly, soot and corrosion can start. Occasional tongues of flame can dance upward, allowing some combustion to occur outside of the chambers where the gas-jet of fire is meant to go. Low levels of carbon monoxide can waft into the home instead of outside.

Years of use, humidity, vent gasses and temperature fluctuations can also stress metals and cause cracks in the heat exchange unit on a furnace. If left undetected, the cracks can grow and allow carbon monoxide to escape where it's not intended.

On many older model furnaces, technicians need an extendable mirror to visually inspect for these cracks in parts of the furnace people cannot readily see.

Carbon monoxide can also leak if flue pipes are not tightly fitted, are cracked or corroded.

Dorry can spot most problems by a visual inspection alone. Much of what he does during an annual inspection is routine. He replaces filters, checks bearings and inspects the various electrical and mechanical parts.

Then, he pulls out a small meter and probe. It measures carbon monoxide levels and tells him what our senses cannot.

He puts the probe first in the flue pipe. A properly functioning furnace will vent carbon monoxide at levels ranging from 25 to 30 parts per million to 50 and 60 parts per million, he said.

Then, he sticks his probe into a register blowing heated air into a room in the house. Here he wants a zero reading.

He's seen cases where leaks vent low levels of carbon monoxide into a home. Residents rarely suspect that their furnace is the cause of the low-grade headaches and allergy-like symptoms they experience.

He urges that everyone install carbon monoxide detectors. It's the only way to know if the gas is present.

"It's odorless and colorless,'' he said.

It's also highly poisonous.

It combines with the blood and blocks the absorption of oxygen. Victims experience flu-like symptoms and mental confusion that can progress to unconsciousness and death.

Our fishing trip to a north woods cabin might very well have ended in tragedy because of it. It was sheer luck that one of us managed to stumble out and in a complete stupor leave a door wide-open.

Luck is great when you're fishing, but don't count on it when it comes to seeing your furnace through a Minnesota winter or protecting your life.