Is Flue gas spillage dangerous even when there is no Carbon Monoxide present?
Also some one told me that our heat exchangers here in Tucson, AZ are rusted out because the furnaces are over sized (winters are pretty mild here).
Any way.... What is the relationship between a heat exchanger being rusted out and the furnace being overs sized?
Also, is the rust on the out side of the heat exchanger from condensation during the cooling cycle?