Hi, sorry you're having trouble....the most common problems I've seen with these is contaminated fuel,,worn spray nozzle or a clogged fuel inlet. If the nozzle is worn the fuel doesn't atomize properly and doesn't burn clean enough to keep the unit lit. Depending on the model..it may have a photo cell to monitor the flame. You can try cleaning it. Here is a link to a couple of websites...they can tell you more in a few minutes than I can explain on this venue. It's very detailed and this is where I go for troubleshooting reference. I hope this helps.