If the oxygen drops to an unhealthy low the oxygen detector will shut off the fireplace.
Vent free gas heater problems.
The log s are out of place and are impinging the flames.
Check the injector holder located at the end of the burner tube.
Vent fee gas logs are not maintenance free.
Blow air through the ports slots and holes in the burner.
Direct vent heaters draw exhaust air outside and blockages in the air vents.
An oxygen depletion sensor ods on unvented gas heaters and fireplaces shuts off the gas flow if the oxygen level drops below 18 an indicator that not enough fresh air is getting into the house but the ods does not detect carbon monoxide or other hazardous emissions.
Shut off the unit including the pilot.
There s basically 4 reasons a vent free gas fireplace will produce soot like you described.
A vent free heater can provide that extra needed humidity.
They must be inspected cleaned annually by a professional gas technician.
The unit hasn t been serviced annually since you purchased it.
Allow the unit to cool for at least 30 minutes.
Inspect burner pilot and primary air inlet holes on injector holder for dust and dirt.