please help, I had my comfortheater checked and the main burners replaced. The pilot light goes on and then shuts off. Finally a repair man came out last year and emptied water from the hose behind the heater and it worked. Now after using air conditioner again and having not used it for another year pilot light doing same trouble. I removed the water behind the gas heater but wont work. I know it something minor and same problem but not able to understand what to do. Blower stays on and cool air just recirculates. What to do next, any advice?