ok first thing, is fire new? if yes then this is not unusual .if you're fire is not new I would suggest turning fire off immediately!!!!!!!.now there may be a possibility of a flue/chimeny blockage another cause could be items pushed or dropped into the fire,kids push things in siilly places .ok no visual signs,.I would call a gas fire engineer as the fire will have to come out and inspected ,also the flue/chimeny will have to be smoke tested for blockages.if you're chimeny is not coweled there is a good possibility that something has fallen down there .
mech monster, October 2011
