Hi, i've had my mes for about 2 months. It's the 1200 watt model. On my first 3 or 4 smokes everything was fine. but last 2 smokes my chips caught fire and even after the fire was out i was making too much smoke and it was not tbs, heavy and white/grey smoke? i didn't do anything differrent . same chips, started with a few to get bed started then added more slowly. any suggestions? thnx