Use and Care Manual
10. GENERAL CARBON MONOXIDE (CO) INFORMATION
Carbon monoxide (CO) is a colorless, odorless, and tasteless poison gas that can 
be fatal when inhaled. CO inhibits the blood's capacity to carry oxygen.
POSSIBLE SOURCES OF CARBON MONOXIDE
Inside your home, appliances used for heating and cooking are the most likely 
sources of CO. Vehicles running in attached garages can also produce danger-
ous levels of CO.
CO can be produced when burning any fossil fuel: gasoline, propane, natural 
gas, oil and wood. It can be produced by any fuel-burning appliance that is mal-
functioning, improperly installed, or not ventilated correctly, such as:
Possible sources include furnaces, gas ranges/stoves, gas clothes dryers, water 
heaters, portable fuel burning space heaters, fireplaces, wood-burning stoves 
and certain swimming pool heaters. Blocked chimneys or flues, back drafting 
and changes in air pressure, corroded or disconnected vent pipes, or a loose or 
cracked furnace exchanger can also release CO into your building. Vehicles and 
other combustion engines running in an attached garage and using a charcoal/
gas grill or hibachi in an enclosed area are all possible sources of CO.
The following conditions can result in transient CO situations:
Wind direction and/or velocity, including high gusts of wind, heavy air in the 
vent pipes (cold/humid air with extended periods between cycles), negative 
pressure differential resulting from the use of exhaust fans, simultaneous opera-
tion of several fuel-burning appliances competing for limited internal air, vent 
pipe connections vibrating loose from clothes dryers, furnaces, or water heaters, 
obstructions in, or unconventional, vent pipe designs which can amplify the 
above situations, extended operation of unvented fuel-burning devices (range, 
oven, fireplace, etc.), temperature inversions which can trap exhaust gasses near 
the ground, car idling in an open or closed attached garage, or near a home.
CO SAFETY TIPS
Every year, have the heating system, vents, chimney and flue inspected and 
cleaned by a qualified technician. Always install appliances according to manu-
facturer’s instructions and adhere to local building codes. Most appliances 
should be installed by professionals and inspected after installation. Regularly 
examine vents and chimneys for improper connections, visible rust, or stains, 
and check for cracks in furnace heat exchangers. Verify that the color of flame 
is blue on pilot lights and burners. A yellow or orange flame is a sign that the fuel 
is not burning completely and may be releasing CO. Teach all household members 
what the alarm sounds like and how to respond. Fire Departments, most utility 










