Carbon monoxide exposure does not necessarily mean death. In fact, the non-deadly symptoms of exposure may help you to determine whether your home is sick. Possible symptoms of low and mid-level exposure are:
If you have a preexisting condition such as a circulatory or lung disease such as asthma or emphysema, your symptoms may be exacerbated by even very low carbon monoxide exposure!
The human body welcomes carbon monoxide the same way it welcomes oxygen. Your blood cannot tell the difference and it merely goes about its business delivering oxygen to your cells only the oxygen is carbon monoxide. You slowly suffocate your body causing damage all the while. You get tired, fall asleep, and can die.
Installed properly and maintained yearly your forced air gas furnace is a very safe, especially if it was built in the last 10 years. Older furnaces lack a great many of the safety controls present on modern furnaces.
Flame Roll Switch: This prevents flames from leaving the firebox chamber and burning the inside of the furnace up.
Electronic Ignition: No standing pilots to burn gas all year long. There are numerous safety controls in the electronic ignition system that prevent excessive large flames, flames too small and burners failing to light.
Vent Diaphragm Switch: Most carbon monoxide poisoning that occurs from gas furnaces occur because the vent is collapsed, plugged or disconnected. Modern furnaces will shut down in the event that the flue isn’t letting the poisons gas outside the home.
Safety Door Switch: If the blower door is left open in a closet area the vacuum created by the blower moor turning on can pull the exhaust right through the vent backwards and distribute the carbon monoxide throughout the home.
Sealed Combustion Chambers: Modern furnaces that are greater than 90% efficient normally have sealed combustion chambers that gather their combustion air from outside the home. This is the greatest degree of safety.
Can Cracks in the Base of the Closet Cause Carbon Monoxide Poisoning: Yes, they can. If the crack is large enough to generate a vacuum when the closet door is closed it can pull carbon monoxide out of the heat exchanger and from the vent allowing it to circulate in the home.
Can Cracks in the Heat Exchanger or Firebox Cause Carbon Monoxide Poisoning: Yes, they can. If the crack is large enough it can pull the flames and carbon monoxide out of the heat exchanger and into the home’s air that you breathe. Most cracks do not suck in carbon monoxide into the home. The most common problem with cracks in the firebox is air blowing into the heat exchanger and blowing carbon monoxide and occasionally the flames out of the furnace into the closet. Once in the closet the carbon monoxide can enter the home through an unsealed closet door or cracks in and around the base of the furnace or a poor sealing blower door.
All blower doors older than 10 years of age seal very badly and are subject to vacuum leaks and can pull carbon monoxide into the home.
If your furnace vents carbon monoxide for any reason into your furnace closet you and your family could be in danger. To tell if you have an unsealed or leaking closet or blower area that is susceptible try this simple and very inexpensive test that you can perform yourself.
You can buy the peppermint extract at any grocery store and you may already have it in your pantry. Do not open up the peppermint extract until you are ready to put it to use testing whether or not you furnace closet is sealed from the blower assembly.
Put the glove on. You don’t want to get the peppermint extract on you because the smell will follow you. Make sure that the blower door is closed and the furnace is turned off. Pour some peppermint extract on the tissue wipe around the base of the furnace and the outside of the blower door. Leave the tissue, the peppermint extract bottle (sealed) and your glove in the furnace closet on the floor. Close the door to the furnace cabinet.
If you have thermostat with a fan switch turn it on now (skip this step if your do not have a fan switch) and walk over the room that has a register in it that is the farthest away from the furnace. If you can smell peppermint extract coming out the vents you have a breech in the area of the closet and the blower assembly. This doesn’t mean you have cracked firebox. It means that the products of combustion, carbon monoxide, have the ability to mix with the air that you breathe.
If you have a heat only furnace with no fan switch perform this test. If you have a fan switch you still need to continue and at this point feel free to turn the fan switch off. Turn the heat on and turn the temperature was up so the furnace doesn’t cycle off too quickly.
Wait for the fan to cycle on once the heat exchange gets hot. Walk over the room that has a register in it that is the farthest away from the furnace. If you can smell peppermint extract coming out the vents you have a breech in the area of the closet and the blower assembly. If you have a fan switch and the smell is greater now that the hat exchanger is hot you may have a crack in the heat exchanger.
This test does not confirm that your furnace is operating under dangerous conditions, but it does give you an easy test that, if confirmed, means that you should look into the situation more closely. A slight presence of the peppermint smell will be present for nearly all furnaces as they all leak a minute amount and this does not indicate a problem. A strong smell definitely indicates a problem.