This allows a hydronic product to be used if the central heating system is not active. The pipe centres featured in this Myson's are based on hydronic products. When
adding heater kits to multi-rails, a T-piece and element will be required that alters the pipe centre dimensions. The difference in pipe centres featured are based on using MYSON valves. These differences may vary on other manufacturers’ valves. For the most efficient operation, one valve should be open and one valve should be closed. Avoid closing both valves.