Why does my CO alarm sound when there doesn’t seem to be a problem?

Remember, CO is an odourless, colourless gas. If your carbon monoxide alarm went off, it detected CO. Make sure no one has any symptoms of CO poisoning.

Here are a few situations that may cause alarms:

The CO alarm needs to be relocated.
The CO alarm should be located 5.5-7 metres (15-20 feet) away from all fossil fuel burning sources like furnaces and stoves. It should be located 3.5 metres (10 feet) away from sources of humidity like showers.

Fossil fuel-burning appliances not burning fuel completely.
Check pilot lights/flames for blue colour. Appearance of blue flames indicates incomplete combustion-a source of carbon monoxide.

The type and age of the CO alarm.
If your CO alarm is one with a SensorPack® Module: The SensorPack® Module should be replaced after 2 years of use. If you have a plug-in alarm: Was the unit unplugged and then plugged in again?