PROCESS HEATER WIRING DIAGRAMS

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					PROCESS HEATER WIRING DIAGRAMS
TYPICAL WIRING DIAGRAMS WITHOUT THERMOSTATS

Process Heaters with Two Elements

                            Single-Phase - Series Connection                             L1 Single-Phase - Parallel Connection
                                   Element Voltage                                                    Element Voltage
                                        Equals                                                            Equals

                                 One Half-Line Voltage                                                Full Line Voltage
                                                                                         L2
                  L1   L2



                                                         Note: Dual-Voltage heaters are factory wired for the highest
                                                         voltage (series connection) unless otherwise speci ed.
                                                         Easily rewired for lower voltage operation (parallel connection).




Process Heaters with Three Elements


                             Single Phase                            Three Phase Delta                              Three Phase Wye
                                                        L1 L1                                    L2


                                                                                                                                           L3


             L2                                                                                  L3
                                                                                                                 L1                   L2




                       Single Phase                                  Three Phase Delta                              Three Phase Wye
                                                   L1           L1                        L2




                                                   L2
                                                                            L3                                 L1         L2          L3



            Standard process style heaters with three elements are factory wired for three-phase
            delta. They can be rewired for single-phase operation with no wattage change. Wattage can be reduced
            to one third of the designed wattage by switching from three-phase delta to Wye connection.




     190 Detroit Street • Cary, Illinois 60013 • Phone: 847-639-5600 • Fax: 847-639-2199 • Web: www.durexindustries.com • TOLL FREE: 800-762-3468   45
     PROCESS HEATER WIRE DIAGRAMS
     TYPICAL WIRING DIAGRAMS FOR HEATERS WITH THERMOSTATS


                       When Heater Amperage Does Not Exceed the Amperage of the Thermostat


                  Fused Disconnect                                                                  Fused Disconnect

                                                           Heater
           L1                                                                              L1

                                                                                           L2
           L2                                                                              L3
                                                                                                                                               Heaters
                                                                                                                           Thermostat
                                           Thermostat                                                                        DPST
                                              SPST

                  120V Single-Phase Heater                                                                   Three-Phase Heater




                              When Heater Amperage Exceeds the Amperage of the Thermostat


           Fused Disconnect
                                                  Magnetic Contactor
                                                                                                Fused Disconnect
      L1
                                                                                      L1
                                                                       Heater
                                                                                      L2
      L2
                                                                                      L3
                                                                                                                                                         Heaters

                                                                                                          Fuses

                                     Thermostat                                                                        Thermostat           Magnetic Contactor
                                       SPST                                                                              DPST


                Any Voltage Single-Phase Heater                                                               Three-Phase Heater


     Use a Single Pole-Single Throw (SPST) thermostat wired                      Use a Double Pole-Single Throw (DPST) thermostat wired
     in series with the holding coil of a magnetic contractor                    in series with the holding coil of a magnetic contractor
     or mercury relay (pilot duty).                                              or mercury relay (pilot dury).




46         190 Detroit Street • Cary, Illinois 60013 • Phone: 847-639-5600 • Fax: 847-639-2199 • Web: www.durexindustries.com • TOLL FREE: 800-762-3468