Where is the required boiler feedwater stop valve located on a high pressure boiler?

The required boiler feedwater stop valve is located between the boiler and the check valve. This placement is essential for several reasons. First, it allows the operator to isolate the boiler from the feedwater supply, which is crucial for maintenance or in situations where the boiler requires servicing. By positioning the stop valve here, it ensures that no water can enter the boiler once it is shut off, providing control over the feedwater system.

Additionally, having the stop valve before the check valve is vital in preventing water from flowing back into the feedwater system, thereby protecting the integrity of the water supply and maintaining system pressure. This location mitigates the risk of backflow, which can lead to contamination of the feedwater and potential damage to the boiler.

In contrast, the other locations presented in the choices do not align with standard practices for boiler operation and safety. For example, placing the stop valve before the pressure gauge would hinder accurate pressure readings and could allow for potentially dangerous situations if the gauge is not functioning correctly. Locating it at the main water supply line could disrupt water flow to multiple systems, complicating repairs and maintenance. Lastly, having the stop valve after the safety relief valve would be ineffective, as the purpose of the safety relief valve is to prevent