New York Low Pressure Boiler COF Practice

What is the standard size of the overflow on an open-type expansion tank?

1. 1/2"

2. 1"

3. 3/4"

4. 2"

The correct answer is: 1"

The standard size of the overflow on an open-type expansion tank is typically 1 inch. This size is established to effectively handle the volume of water that may overflow from the tank due to temperature changes and the resulting expansion of water. An overflow of this size ensures that any excess water can adequately drain without causing pressure build-up or risking the integrity of the system. In practical applications, using a larger or smaller overflow could lead to inefficiencies or potential complications; for example, a 1/2" overflow might not be capable of handling sufficient flow during peak conditions, while a 2" overflow could be unnecessarily large, leading to increased costs and complexity without added benefit. Thus, the choice of a 1" size aligns perfectly with standard industry practices for maintaining safety and performance in low-pressure boiler systems.