I just installed 2 of these. Vendor was great about providing a replacement after testing the first one's sensor failed. Test: I held butane lighter (after blowing out flame) about 2" from sensor for a full minute but the horn never sounded. Manual states 3-4 seconds and red warning light will come on. About 10 seconds and alarm will sound. After a minute, I stopped test. No alarm and I was in an enclosed helm area. No wind! Green light stayed on. No red light or audio alarm. I tried about 1/2 oz gasoline in a cup and held sensor over it. The results were the same. Vendor sent me replacement and tried butane test again and still no alarm sounded. I held lit match near butane lighter and flame came back so there is no doubt that lighter is emitting fumes. Have any experience Xintex issues? If I am doing something wrong, I want to correct my test methods. However, Xintex may have a batch of bad Chinese made sensors.