What is required for non-catalytic low emission appliances?

For non-catalytic low emission appliances, maintaining a firebox temperature above 1,100°F is essential to ensure efficient combustion and minimize emissions. This high temperature facilitates the complete burn of the fuel and helps to effectively reduce the production of carbon monoxide and particulate matter. The combustion process relies on achieving and sustaining this temperature to ensure that the gases produced during burning are fully oxidized.

In non-catalytic systems, the design typically incorporates features that promote high temperatures and sufficient air supply, allowing for a more efficient combustion process without the use of catalytic converters. This method not only aids in achieving low emissions but also enhances the overall performance of the appliance.

The other choices do not align with the requirements for non-catalytic appliances. Using liquid fuel exclusively would restrict these appliances to a specific fuel type, which is not a requirement. Likewise, avoiding air mixing and using multiple catalysts simultaneously are not characteristic of non-catalytic designs; these systems are specifically engineered to function effectively without catalysts and often utilize an optimized air supply for combustion.