What are package boilers programmed to do upon start-up?

Package boilers are designed with safety and efficiency in mind, especially during start-up procedures. When a package boiler starts up, it is programmed to ignite the burner in low fire. This approach allows the boiler to carefully and gradually reach operating temperature while minimizing the risk of thermal shock and allowing for adequate mixing of fuel and air, which leads to a more efficient and controlled combustion process.

Starting in low fire helps prevent excessive pressure and temperature rises that could occur if the boiler were started in high fire. It also ensures that any potentially unburned fuel can be managed effectively, thereby enhancing safety and reducing emissions during the initial phase of operation. This characteristic is crucial for maintaining the integrity of the boiler system and ensuring compliance with environmental and operational standards.

The other options, while potentially relevant in different contexts, do not reflect standard practices for package boiler start-up.