These heaters run on propane canisters and usually work great. Mine did for a year or so and then the pilot light started burning yellow, and the heater would just go out randomly after a few minutes. It had gotten dirty out on my patio. I cleaned the outside, but the inside apparently needed cleaning too. I read the fix on their website. Lower the front protective grate (pops out at the top if you lift up), and run a q-tip swabbed in alcohol down the pilot tube a couple inches. (I had to remove some cotton to make it fit.) Twist, and remove. My q-tip came out dirty. After it dried, I fired it up, and it was like new! Blue pilot flame, and the heater runs well. I had been about to throw it out in frustration. Maybe someone in the same situation will read or google upon this and save a good heater.