Red Seal Oil Heat System Technician Practice Exam

What does "kettling" refer to in a boiler?

1. The formation of rust in the boiler

2. The boiling of water inside the boiler due to overheating or low water levels

3. The development of steam pressure in the system

4. The production of excessive emissions

The correct answer is: The boiling of water inside the boiler due to overheating or low water levels

Kettling in a boiler primarily refers to the boiling of water inside the boiler caused by overheating or low water levels. This phenomenon occurs when the water in a boiler is subjected to heat that exceeds its normal operating temperature, leading the water to boil rapidly. If the water levels are too low, the heat can cause localized boiling, which can create steam bubbles that collapse violently—this is often described as “kettling” because the sound resembles water boiling in a kettle. The implications of kettling are significant; it can lead to increased wear and tear on the boiler components, reduced efficiency, and ultimately, potential damage to the system if not addressed. Identifying and rectifying the cause of kettling is crucial for maintaining safe and efficient operation within a heating system. Understanding this concept is essential for diagnosing performance issues in oil heat systems, enabling technicians to ensure effective and safe operation.