No-one had told one of my FIs that his OMQ had a back boiler. As soon as the temperature dropped with the onset of Autumn, he lit the fire and settled down with his wife to watch TV. After a little while they were nice and warm, but a bit perturbed by the mysterious gurgling noises they could hear.......until with an almighty bang the whole thing blew up and his wife was hit by a piece of red hot shrapnel from the wretched thing, which scarred her for life.