I have a 2 year old heatilator cab 50 that i bought new. The first season it worked flawless. Last year it started out working fine but as the season went on it started acting up. It first started with the high setting, it would start up on high but will quit feeding and shut off. But medium and low still worked great. Then the exact same thing happend on medium, it would start then quit feeding and shut off. Now it only works on low. Any ideas? I cleaned it all out and its still the same. Thanks!