That's one reason why I had the boiler replaced in my older house when we bought the place. I didn't want something that potentially explosive sitting in my home. I remember when I was in school, we couldn't have any events at night unless a certified boiler mechanic was on duty. I thought if they needed someone to watch over a boiler at a school, then what could happen with an unsupervised boiler in my own house? I'm not trained to look out for things like water levels or heat settings.