Pump control system

Claim 1

IN AN AIR CONDITIONING SYSTEM INCLUDING FIRST AND SECOND ZONES OF BE CONDITIONED, A PLURALITY OF HEAT EXCHANGE UNITS IN EACH OF SAID ZONES, A FIRST CONDUIT MEANS FOR SUPPLYING A WARM HEAT EXCHANGE FLUID TO EACH OF SAID HEAT EXCHANGE UNITS IN EACH OF SAID ZONES, A SECOND CONDUIT MEANS FOR SUPPLYING A COLD HEAT EXCHANGE FLUID TO EACH OF SAID EXCHANGE UNITS IN EACH OF SAID ZONES, SEPARATE VALVE MEANS CONNECTED TO EACH OF SAID HEAT EXCHANGE UNITS AND TO SAID FIRST AND SECOND CONDUIT MEANS TO SELECTIVELY SUPPLY WARM OR COLD HEAT EXCHANGE FLUID TO SAID HEAT EXCHANGE UNITS AS REQUIRED, A HEATER, A COOLER, MEANS CONNECTING SAID HEATER TO SAID FIRST CONDUIT MEANS, MEANS CONNECTING SAID COOLER TO SAID SECOND CONDUIT MEANS, THE IMPROVEMENT COMPRISING: A FIRST COMMON RETUNR CONDUIT MEANS OPERABLY CONNECTED TO EACH OF SAID HEAT EXCHANGE UNITS OF SAID FIRST ZONE FOR RETURNING SIMULTENEOUSLY SPENT WARM AND COLD HEAT EXCHANGE FLUID THEREFROM; A SECOND COMMON RETURN CONDUIT MEANS OPERABLY CONNECTED TO EACH OF SAID HEAT EXCHANGE UNITS OF SAID SECOND ZONE FOR RETURNING SIMULTANEOUSLY SPENT WARM AND COLD HEAT EXCHANGE FLUID THEREFROM; AND THERMOSTATICALLY CONTROLLED PUMP MEANS CONNECTED TO BOTH OF SAID COMMON RETURN CONDUIT MEANS TO RETURN WARM HEAT EXCHANGE FLUID FROM SAID COMMON RETURN CONDUITS PREDOMINATELY TO SAID HEATER AND COLD HEAT EXCHANGE FLUID PREDOMINATELY TO SAID COOLER IN RESPONSE TO TEMPERATURE OF THE HEAT EXCHANGE FLUID IN THE RESPECTIVE COMMON RETURN CONDUIT MEANS.