Q: My Carbon Monoxide Detector is alarming. What should I do?

A: A Carbon Monoxide (CO) detector reading warrants looking at all of the factors involved, which include the gas log set; the environment in which the gas log set operates; the CO detector; and other sources of CO in and around the house.

Please view the attached troubleshooting information.

Additionally, please look at and consider the following:

• Inspect the air intakes around the burner air shutters. If they have become clogged with lint or dust it can negatively impact combustion performance.
• We have had cases where the cause of the CO alarm going off was the mantle overheating and cooking off (off-gassing) the varnish.
• Please ensure that the installation instructions have been followed, especially with regard to the cleanliness of the firebox, the size of the firebox, the placement of the logs and the installation of the glowing embers (small, loose pieces).

The national unvented heater standard (ANSI Z21.11.2) to which all Chillbusters are certified, has the strictest limits for Carbon Monoxide (CO) of all gas burning appliances. The CO limit for a gas burning kitchen range (also an unvented appliance) allows four times the CO permitted for an unvented heater. The ANSI standard allows up to 25 ppm of CO to be present in the combustion gases of an unvented heater.

Carbon monoxide will be present in all types of burning. A person inhales 2000-6000 ppm of CO with each puff of a cigarette. I have measured candles giving off up to 25 ppm of CO. Government guidelines allow up to 35 ppm exposure in an eight hour period.

A new Nighthawk CO detector needs a seven day warm-up period before reading will have any accuracy. They have a stated accuracy tolerance of +/- 35% for readings from 0 to 150 ppm. They can be unduly influenced by vapors from petroleum, alcohols, household aerosols or increased indoor humidity (of which a vent-free gas log set contributes one quart of water every hour when burned at 40,000 BTU/hour).

The most common cause of elevated CO readings in a house is due to automobile exhaust from attached garages. The second most is cigarette and cigar smoking indoors.