Do you open the flue on a gas fireplace?
Similarly, is it safe to close the flue on a gas fireplace?
Because gas-log fires produce copious amounts of carbon monoxide, they have to vent outside in a fail-safe manner. That's why there is, or should be, a keep-open device attached to the damper in gas-log fireplaces. Do not close a fireplace damper until the fire is completely out.
In this way, can you close the damper when pilot is on gas fireplace?
If you have installed gas logs in your fireplace, the damper should never be closed. If you have a pilot light constantly burning under your gas logs, shutting the damper puts you, your family and your pets at severe risk of carbon monoxide poisoning.
Yes, gas fireplaces are one potential cause of carbon monoxide poisoning. An improperly maintained or ventilated gas fireplace, however, can result in incomplete combustion, creating carbon monoxide, and causing this toxic gas to linger—putting those inside at risk of carbon monoxide poisoning.