Minnesota Boiler License Practice Exam

What is the purpose of an isolating valve?

1. To isolate the expansion tank (while a boiler is in operation) so that it can be drained

2. The isolating valve shuts off the hot water boiler

3. The isolating valve shuts off the boiler feed water pump

4. None of the answers given

The correct answer is: To isolate the expansion tank (while a boiler is in operation) so that it can be drained

The primary purpose of an isolating valve is to allow for maintenance or repairs by isolating a specific section of the system from the rest. In the context of the question, the isolating valve is designed to isolate the expansion tank from the boiler system while the boiler is in operation. This capability enables technicians to safely drain or maintain the expansion tank without interrupting the overall operation of the boiler. By isolating the expansion tank, the valve ensures that the rest of the boiler system remains functional, minimizing downtime and potential impacts on heating operations. Its role is crucial during maintenance activities, enhancing safety and efficiency. The other options focus on functions that are not typically associated with isolating valves. For instance, while shutting off the hot water boiler or the boiler feed water pump may be necessary in certain scenarios, these actions are usually managed by different types of valves or controls specifically designed for those purposes. Thus, the isolating valve's specific function is to provide a safe means to maintain and service the expansion tank while keeping the boiler operational.