Where is the feed water stop valve typically located?

The feed water stop valve is designed to control the flow of water into the boiler, and its typical placement is between the boiler and the check valve. This location is crucial because the check valve serves to prevent any backflow of steam or water from the boiler into the feed water line. By placing the feed water stop valve between the boiler and the check valve, you ensure that the feed water can be shut off safely without allowing the possibility of backflow, which could lead to dangerous situations such as boiler overpressure or contamination in the feed water system.

Positioning the stop valve in this manner also allows for effective maintenance and operational control. If maintenance is needed on the boiler or check valve, having the stop valve in this position enables operators to isolate the boiler from the feed water supply easily.

The other options involve incorrect placements that do not effectively provide the necessary functionality or safety required in this critical system. For instance, placing the valve at the steam outlet or near the water treatment system would not allow for proper isolation and control of feed water, which is critical for safe boiler operation. Furthermore, a location before the safety valve could compromise the safety mechanism needed to prevent potential overpressure situations in the boiler, which is essential for safe and effective operation.