I've moved into a house with a wall-hung flue less gas fire. I haven't had one of these before. I'm off to buy a CO detector but in the meantime, can you tell me about these? What colour is the flame supposed to be? When I light this it has a yellow flame. I thought this was supposed to be a bad thing as I thought yellow meant it was not burning completely. However there are no signs of soot above the fire nor inside it and pictures I have found of similar fires on google show yellow flames too. I guess if the flames burnt pale blue, people would not see the flames, so they wouldn't look as pretty. Do ukdiy-ers vacuum the fire once a year like you may do to your boiler or is it best to leave it to a gas safe person. I'm sure the CO alarm will reassure me, just wanted to hear some opinions in the meantime.