What is the potential consequence of not properly venting a boiler coming offline?

The formation of a vacuum can occur if a boiler is not properly vented as it comes offline. When a boiler shuts down, especially if it cools down too quickly, the steam or hot water inside can condense, leading to a decrease in internal pressure. If the venting system does not allow for the escape of air or steam, it can create a situation where the pressure inside the boiler becomes lower than the atmospheric pressure outside. This difference in pressure can result in a vacuum forming within the boiler, which can potentially cause structural damage, impede normal operation, and complicate maintenance procedures. Proper venting ensures that air can enter and maintain an equilibrium, preventing the negative consequences associated with vacuum formation.