What type of valve is required for each boiler supply and return pipe connection?

The use of a stop valve for each boiler supply and return pipe connection is essential due to its functionality and operational reliability in hydronic systems. A stop valve is designed specifically to shut off the flow of water in a piping system, making it appropriate for isolating the boiler when maintenance or service is required. This capability ensures safety and efficiency by allowing personnel to perform necessary work without draining the entire system or risking leaks.

Stop valves generally provide a simple mechanism for operation and can maintain tight seals, which is crucial in preventing leaks in a pressurized system like one involving boilers. They can also handle varying flow conditions without causing significant pressure loss.

In contrast, while ball and gate valves are also capable of isolating flow, they may not be as optimal in environments where precise control and maintenance are necessary. Butterfly valves are better suited for applications requiring throttling capabilities and may not close as tightly as stop valves, which could lead to potential leakage.