I have the back panel open. The smell is coming from middle bottom behind the blower so to speak. Need to know what is under what is covered with black insolation. Dont want to pull that off unless I might need to replace. Ive had co detector come on after 1 hour. Had a pellet person come but he thought it was the piping and we redid but now im still smelling and got almost to the source but cant figure out where its coming from. I can take a pic if needed.