A thermostatic radiator valve (TRV) can control the temperature at each radiator. The most common type has an operator with the setpoint dial mounted directly onto the valve body (top). Also available is a remote setpoint dial, which is connected to the valve by a capillary tube (above). INNOVATIONS IN HYDRONIC HEATING by John Siegenthaler New European valves allow easy and economical room-by-room zoning JLC ??MARCH 1992 Amodern "one-pipe" heating system combines new control technology with an old hydronic (hot water) piping system. This system offers a number of advantages over conventional hydronic systems. In particular, it is cheaper to create heating zones within a building, and it is easier to control these zones independently. The heart of the new system is a