FAA AMT (Aviation Maintenance Technician) Airframe Practice Exam

What prevents too much air from entering the heaters in a combustion heater's air system as air pressure increases?

1. Air filter

2. Combustion air relief valve or a differential pressure regulator

3. Temperature control valve

4. Pressure control switch

The correct answer is: Combustion air relief valve or a differential pressure regulator

As air pressure increases, the combustion heater's air system needs to be regulated to prevent too much air from entering the heater. While options A, C, and D may all seem like viable solutions, they do not specifically address the issue of air pressure. An air filter may help improve air quality, but it will not regulate air pressure. A temperature control valve may regulate the temperature, but it does not directly control air pressure. The pressure control switch may control the pressure, but it is not specific to air pressure and may not be able to handle the increase in pressure from the combustion heater. On the other hand, option B, a combustion air relief valve or a differential pressure regulator, is specifically designed to regulate air pressure and ensure that the combustion heater receives the appropriate amount of air to operate efficiently. Therefore, option B is the most suitable answer in this scenario.