What CO2 content in exhaust gases is expected in a Category IV LP unit with 50% excess air?

In a Category IV LP (liquid propane) unit operating with 50% excess air, the expected CO2 content in the exhaust gases is typically found in the range of 10% to 14%. This range is indicative of the combustion efficiency in conditions with a balanced supply of air. Excess air is added to ensure complete combustion, which can dilute the concentration of carbon dioxide produced during the combustion process.

In this scenario, while 50% excess air promotes complete combustion by providing additional oxygen, it also means that the resultant concentration of CO2 in the exhaust will be lower than in a situation without excess air. Achieving a CO2 level within this range is consistent with the combustion characteristics of propane when enough oxygen is available, promoting cleaner combustion and lower emissions.

Other ranges suggested in the choices reflect scenarios of incomplete combustion or conditions with insufficient oxygen, which are not representative of the operating conditions of a Category IV LP unit with the specified excess air. Therefore, the range of 10% to 14% accurately reflects a scenario of efficient combustion with adequate excess air.