A coil type boiler with a capacity less than 400 MBtu would need which component?

For a coil type boiler with a capacity of less than 400 MBtu, it is essential to incorporate a flow sensor and a high limit control. The flow sensor is crucial because it monitors the flow of water through the boiler. This is vital for preventing overheating and ensuring the safety and efficient operation of the system. If there’s inadequate flow, the boiler could potentially overheat, leading to unsafe conditions.

The high limit control is equally important as it acts as a safety mechanism that shuts down the boiler if the water temperature exceeds a predetermined limit. This feature prevents mechanical failure and ensures safe operation of the boiler.

While other combinations listed may include components that serve important functions in various boiler systems, the specific safety measures required for a coil type boiler under 400 MBtu emphasize the need for both a flow sensor to monitor and ensure there's adequate water flow throughout the system, along with a high limit control to prevent excessive temperatures. Each component performs a distinct role in maintaining a safe and efficient operational environment, which is critical in adhering to safety standards in boiler operation.