Heating and cooling system and control therefor

Claim 1

A HEATING AND COOLING SYSTEM COMPRISING FOUR FLUID MAINS, INCLUDING A SUPPLY AND RETURN MAIN FOR HEATING FLUID, AND A SUPPLY AND RETURN MAIN FOR COOLING FLUID, A PLURALITY OF HEAT EXCHANGERS AT DIFFERENT LOCATIONS IN THE SYSTEM FOR CONTROLLING THE TEMPERATURES OF DIFFERENT SPACES, AND SEPARATE VALVE MEANS CONNECTING EACH OF THE HEAT EXCHANGERS WITH THE FLUID MAINS, EACH OF THE VALVE MEANS HAVING SIX PORTS CONNECTED, RESPECTIVELY, WITH THE FOUR MAINS AND WITH OPPOSITE ENDS OF THE HEAT EXCHANGER, THE VALVE MEANS BEING MOVABLE INTO A FIRST POSITION TO CON NECT THE OPPOSITE ENDS OF THE HEAT EXCHANGER WITH THE SUPPLY AND RETURN MAINS FOR THE HEATING FLUID, AND BEING MOVABLE INTO A SECOND POSITION TO CONNECT OPPOSITE ENDS OF THE HEAT EXCHANGER WITH THE SUPPLY AND RETURN MAINS FOR THE COOLING FLUID, THE VALVE MEANS BEING MOVABLE INTO A THIRD POSITION INTERMEDIATE ITS FIRST AND SECOND POSITIONS AND IN WHICH IT BLOCKS FLOW OF BOTH HEATING AND COOLING FLUID TO THE HEAT EXCHANGER, THE VALVE MEANS HAVING A PASSAGE THAT CONNECTS THE PORT THAT IS IN COMMUNICATION WITH THE HEATING FLUID SUPPLY MAIN DIRECTLY TO THE PORT THAT IS IN COMMUNICATION WITH THE HEATING FLUID RETURN MAIN WHEN THE VALVE MEANS IS IN ITS THIRD POSITION, AND THE VALVE MEANS ALSO HAVING A PASSAGE THAT CONNECTS THE PORT WHICH IS IN COMMUNICATION WITH THE COOLING FLUID SUPPLY MAIN DIRECTLY TO THE PORT WHICH IS IN COMMUNICATION WITH THE COOLING FLUID RETURN MAIN WHEN THE VALVE MEANS IS IN ITS THIRD POSITION.