Ceramic logs must not be positioned over the flames. On smaller models it may be that the bio logs are placed on the burner box flap. That is fine, as long as the hook can still connect with the points on the box to close the fire off. It may be that closing the fire off dislodges the logs and these will simply need re-setting when they are cold. In most cases the flap will only need moving once, before the burn cycle, as bio stoves do not need constant air adjustments like wood burning stoves.