Fuel-fired appliances must be designed for use with the type of fuel and what other condition?

Fuel-fired appliances are engineered to operate efficiently and safely with a specific type of fuel, and altitude is a critical factor in this design. As altitude increases, the air density decreases, which can affect the mixture of fuel and air necessary for optimal combustion. Appliances designed for use at higher altitudes may require adjustments in their operation, such as different burner settings or modifications to gas pressure, to ensure that they function correctly and do not produce harmful byproducts.

At lower altitudes, fuels may burn differently due to the higher density of oxygen, leading to variations in performance and efficiency. Therefore, manufacturers often stipulate different appliance settings or models specifically tailored for use at various altitudes. This consideration is crucial for maintaining safety standards, performance efficiency, and reducing the risk of malfunctions or hazardous emissions in fuel-fired appliances.