I have just had a gas fire put in and the coals go black when it is alight?

they will to a certain extent you can't have a "coal fire flame effect" without producing soot like the real coal fires did most of it will burn off if you have the fire on max. every now and then but check coal placement with handbook and try not to block the flames too much the more the yellow floppy flames touch the coals the more soot is produced

brian
February 2011