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351579-YTS-B-0608Single Enthalpy: the control will consider, along withoutside temperature, outside air humidity [OAH sensor;parameter must be set to ON] in enabling free cooling.The outside air enthalpy setpoint parameter [BTU perpound] must also be set.NOTE:For smoke purge, etc., special connections: for standardcontrols, consult a controls specialist familiar withyour local codes.Dual Enthalpy (Comparative/Differential Enthalpy):Both the Outdoor Air Enthalpy and the Return AirEnthalpy [RAH sensor, option parameter must be set toON] are connected to the control. The setpoint when theoutdoor air enthalpy is less than the return air enthalpy,free cooling is available. The rules in the control will lockout free cooling and force mechanical cooling when theoutside air temperature exceeds setpoints.19. Power Exhaust Option with Modulating Dampers: Thepower exhaust controls are enabled in Occupied mode. Thebuilding pressure sensor [BSP] provides a signal to the control.The exhaust dampers are modulated by a 2-10VDC signalfrom the control, proportional to the pressure sensed, tothe damper actuator. When the actuator opens the dampermore than the parameter “Exhaust Damper Position forExhaust Fan to Turn ON” setting, the Simplicity ® controlpowers the 10M starter to engage the power exhaust fanmotor. When the dampers reach the ”Exhaust Damper Positionfor Exhaust Fan to Turn OFF” setting, the control turnsthe motor off. When the power exhaust is disabled, the controlcloses the exhaust dampers.20. Non-Modulating Power Exhaust Option: The powerexhaust controls are enabled by the Simplicity ® control.The control powers the exhaust fan motor by monitoringthe position of the economizer damper vanes [“EconomizerDamper Setting for Exhaust Fan to Turn ON [OFF]”]. Theoutlet pressure of the power exhaust fan forces the barometricrelief dampers open. Exhaust Fan operation is continueduntil the economizer reaches the % set in theparameter Gravity closes the barometric relief damperswhen the exhaust fans are off.21. Power Exhaust Option with Variable Frequency Drive(VFD): The power exhaust controls are enabled throughthe Simplicity ® control. The variable frequency drive is controlledby a signal from the control, based on the BuildingPressure sensor (BPS), located in the control box, whichtranslates the building pressure signal to a VDC signal.Fine tuning is accomplished by setting parameters in theVFD [ref: separate instruction].NOTE:Modulated exhaust: Pressure-tap tubing must be runfrom an appropriate location in the building to the"high" port on the BPS transducer. Dampers on theVFD power exhaust are gravity-closed and are notmodulated. The BPS signal is proportional with the differencebetween outside ambient pressure and buildingpressure. The VFD is set for a minimum speed of33% and a maximum of 100%. The VFD parametersare factory set, specific for each control system, andare detailed on a sticker by the drive. The drive manualis shipped with the unit.HEAD PRESSURE CONTROL, R22 (R410A)DESCRIPTIONThe head pressure control option controls the speed ofcondenser fan 1 for low ambient mechanical cooling operationof systems 1 and 2. This option functions independently of theSimplicity® control.The option includes two pressure transducers and a variablefrequency drive. The pressure transducers are connected to thedischarge line of system 1 and 2. The VFD modulates to thehigher signal; if either system 1 or 2 exceeds 280 psi R22 (360psi for R410a), a secondary mechanical switch close to turn onfan 2. Typically the modulated fan will slow down; if bothsystems drop below 180 psi, fan 2 drops out.System 3 on a 30 ton R22 and system 3 and 4 on a 40 ton R22(and all R410a units) are locked out below 45°F ambient.NOTE:All power exhaust options require that the customerprovide tubing connections to the transducer from arepresentative location in the building; modulatingvaneand VFD exhausts will open full / power on inPurge mode.Altering the factory settings could result in poor controlor operation of the system.No special motor is required on three-phase systems; singlephase systems will use three phase motors on fan 1. TheVariable Frequency Drive is pre programmed at the factory.SEQUENCE OF OPERATION - FOR HEAD PRESSURECONTROLA call for the first stage cooling powers the 6M contactorenergizing the variable frequency drive. The drive will ramp tothe pre programmed minimum speed of 20 Hertz immediatelyupon start up. As the discharge pressure on system 1 or 2compressor rises, the transducer output signal to the variablefrequency drive rises. The drive will increase the speed ofcondenser 1 fan, maintaining a setpoint of 240 psi R22 (325 psiR410a).The scroll compressor produces a rapid rise in dischargepressure upon start up. This usually will result in full speedoperation of condenser fan 1. After the discharge pressure hassettled out, the speed of condenser 1 may decrease especiallyduring times when the ambient temperature is below 80 °F. Afterthe 1 system has stabilized and compressor 2 is energized, thespeed of condenser Fan 1 will increase to compensate for thedischarge pressure rise. Typically, since fan 2 will run at fullspeed, fan 1 will slow down when fan 2 energizes.26 Johnson Controls Unitary Products
351579-YTS-B-0608As the ambient temperature dips below 40 °F the 1 condenser fanwill slow to the minimum speed. The circuit 2 condenser fan willdisengage when the discharge pressure drops below 180 psi R22(300 psi R410a) as the ambient temperature falls. The dischargepressure of system 1 and/or 2 will increase when condenser fan 2stops, consequently causing an increase in the speed ofcondenser fan 1.The Millennium ® Simplicity ® control includes a terminal SD forthe user to wire a signal to shut down, and a Purge terminal tosignal the unit to shut off heat or mechanical cooling, open theeconomizer and exhaust dampers, and run the exhaust fan[depending on which options are installed on the unit].INTELLI-STARTIf Intelli-Start is enabled the control will use that calculation todetermine when to start Morning Warm-Up. If the Intelli-Startoption is not enabled, the control will start Morning Warm-Upone hour before Occupancy.When Intelli-Start is enabled, the control will attempt to recoverthe building to the Occupied Setpoint by the time the Occupiedperiod begins. On the first day when the control has nothingstored for recovery, it will go “Occupied” two hours before theOccupied period. The control will store the beginning demandand track the time it takes to reach the Occupied Setpoint.When the Occupied setpoint is reached, the control will storehow long it took, and use that warm-up ability to calculate theperiod needed the next time it runs. The control will store therecovery value separately for Heating and Cooling. UnoccupiedRecovery will only run on the first Occupied period of the day. Itwill always be operating on the previous day’s performance.The Economizer will be used if free cooling is available.Millennium ® Simplicity ® will accommodate inputs for water coilfreeze stat, SA sensor, ODA sensor, Space sensor, and Roomsensor, Building pressure sensor, Duct pressure sensor,Demand ventilation, RA humidity, OD humidity, RS485communications.LEAD LAGWhen this option is set ON, the unit will equalize run time oncompressors [except for compressor 1 if the head pressurecontrol option or hot gas bypass is installed].DEVICES AND RULESThis chapter describes the many control modes of operation forSimplicity ® . Because of the narrative and detailed descriptionscontained in this section, you should only scan this chapter andbecome familiar with the primary topics. Then, use this chapteras a reference whenever a more detailed understanding of aparticular mode is needed.You should keep in mind that, especially with digital controls,interlocking between control modes is common and easilyachieved. Also, by the very nature of digital controlprogramming, many simultaneous rules can be implementedbecause they generally require only software programming andvery little peripheral hardware. This reduces the costsassociated with manufacturing and servicing equipment withthis level of interacting features - but you can’t see the status ofinterlocked rules as you can with discreet relays.Several control modes will override other modes of operation.For example, The Demand Ventilation (or, Indoor Air Quality)control may override Comfort Ventilation / Economizer controland drive the OA dampers above the established minimumposition. The Excessive SAT control will override alltemperature control modes, Economizer mode, andcompressor operation as well. If you suspect that a problemexists with the economizer, or the compressors are locked outwhen no alarms are set, verify that one of the control modes isnot overriding the normal mode of operation or the operationyou might expect to see. Another important example is the AirProving Switch interlocking mode. If the Air Proving Switchalarms on a VAV unit, the unit will refer to the duct pressuresensor; if duct pressure is present, the control will assume thefan is working even though the APS is not.If the fan status [APS] fails, and the duct pressure switch of aVAV unit sees no duct pressure, all controlling algorithms andoperations, and outputs (except hydronic heat) will cease andthe control will shut down all outputs.AIR PROVING SWITCHWhen the control starts the supply fan, it waits 90 seconds tocheck for closure of the Air Proving Switch (APS). If the APSdoes not close, the control will turn off all outputs except Fanand the VFD speed signal, flag an alarm, and flash an alarm onthe display. If it is a VAV unit, the control will look to the ductpressure signal; if it is above .05”, the control will flag a badAPS and continue operation.It will retry the Fan output every 30 minutes for three retries. Ifafter three retries it still cannot qualify the Fan, it will Alarm andlock all heating and cooling operation out. If the switch closesafter an alarm has been flagged, the control will resume normaloperation and clear the active alarm.After the control has turned off the fan, it will wait 90 secondsand verify that the switch opens. If the switch does not openafter 90 seconds, the control will flag a failed switch and flashthe alarm. On the next startup, the control will stage upequipment normally.This switch-closed failure mode of the Air Proving Switch canonly be detected with the Supply Fan off. It is important todetect because it effectively disables the fan failure alarmchecking while fan is running, described in the paragraphsabove. Those checks would always pass as the switch wouldremain closed. In networked applications, the error flag isreadable by the network. The alarm will automatically reset afterthe problem that caused it has been corrected.When the control is running the fan and the APS has alreadybeen proven, and then it opens, the control will wait 2 secondsbefore shutting down heating, cooling, and locking out. It willalarm and retry as if it happened during start-up.Johnson Controls Unitary Products 27
Page 1 and 2: 351579-YTS-B-0608TECHNICAL APPLICAT
Page 3 and 4: 351579-YTS-B-0608THE MILLENNIUM ®
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Page 7 and 8: 351579-YTS-B-0608ANALOG INPUTS (AI)
Page 9 and 10: 351579-YTS-B-0608Table 3: Simplicit
Page 11 and 12: 351579-YTS-B-0608SIMPLICITY ® PROG
Page 13 and 14: 351579-YTS-B-0608be turned off by t
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Page 17 and 18: 351579-YTS-B-0608Table 5: Settable
Page 19 and 20: 351579-YTS-B-06082. Mechanical cool
Page 21 and 22: 351579-YTS-B-0608determined by the
Page 23 and 24: 351579-YTS-B-0608Pressure Switch -
Page 25: 351579-YTS-B-0608Table 9: Modulatin
Page 29 and 30: 351579-YTS-B-0608mizer damper and u
Page 31 and 32: 351579-YTS-B-0608TYPES OF SPACE SEN
Page 33 and 34: 351579-YTS-B-0608UNOCCUPIED HEATING
Page 35 and 36: 351579-YTS-B-0608Table 12: Holiday
Page 37 and 38: 351579-YTS-B-0608The RAH sensor, if
Page 39 and 40: 351579-YTS-B-0608for economizer loa
Page 41 and 42: 351579-YTS-B-0608time 60 seconds (N
Page 43 and 44: 351579-YTS-B-0608TROUBLESHOOTING A

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