I just bought the house 6mo ago.used to work fine for inspection at the time.This winter it wouldn't get started. called the trane technician to inspect. He put on the burner but said that it's furnace has 2 tiny cracks in it so would be unsafe to start and needs to be replaced. Well just to be sure I started it. worked fine but carbon monoxide meater started reading 37-47 units on it. I guess flames go into the blower . WELL CANT IT BE WELDED OR SOMETHING . DO I REALLY HAVE TO BUY NEW ONE. TRANE HEATERS ARE SO EXPENSIVE. WHAT OTHER PLACES DO I SEARCH.PLEASE HELP ME.