TEC Zoning Control System for Stand-Alone and BACnet® MS/TP ...

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It is possible to adjust the system to completely eliminate heating and coolingequipment cycling based on the outside air limitations, if this type of systemoperation is desired. Figure 6 illustrates two ways to eliminate overlappingdeadband and the associated equipment cycling. Note that eliminating overlappingdeadband may impact the control performance of certain zones during otherperiods of system operation.Heating Lockout =72°F (22°C)No Overlapping DeadbandCooling Lockout =72°F (22°C)Outside Air TemperatureHeating Lockout =70°F (21°C)5F° (3C°)Deadband;No HeatingandNo CoolingCooling Lockout =75°F (24°C)FIG:no_ovrlppng_ddbndOutside Air TemperatureFigure 6: No Overlapping DeadbandSeasonal ChangeoverHeating and cooling equipment cycling during seasonal changeover is almostinevitable with a VAV zoning control system, if any degree of occupancy comfortis to be maintained. A properly set up system delivers comfort to conflicting zonedemands during seasonal changeover by alternating between heating and coolingat the rooftop controller.Unwanted heating and cooling switchovers are eliminated by either using andauthorizing terminal reheat, or by limiting the rooftop controller heating andcooling capacity throughput based on the outside air temperature (H lock andC lock parameters). Note that limiting the rooftop controller heating and coolingcapacity throughput based on the outside air temperature may impact the controlperformance of certain zones in the system, since the required heating or coolingcapacity is no longer available due to the lockout conditions.40TEC Zoning Control System for Stand-Alone and BACnet® MS/TP Networked ApplicationsTechnical Bulletin
Typically, the number of rooftop controller heating and cooling switchover cyclesduring conflicting demand periods is approximately the same as the number ofheating and cooling cycles per hour (Heat cph and Cool cph parameters). Thedefault for Heat cph and Cool cph is four cycles per hour, meaning two heatingcycles and two cooling cycles within a 1-hour period.The recorded rooftop controller change in supply temperature and demandvariances is always higher when using the Highest demand control-type operationversus the Average demand method calculations. Energy consumption is alsohigher with the Highest demand control-type operation versus the Average demandmethod calculations.Bypass Damper Control and OperationThe rooftop controller has a built-in static pressure control loop with an analog0 to 10 VDC bypass damper output. For proper operation, the static pressurecontrol loop must have a static pressure sensor connected to the static pressureinput (Terminal SP) on the rooftop controller. Typically, the static pressure sensorprobe is installed approximately two-thirds the way down the main ventilationtrunk.The required static pressure transducer needs to be a voltage type (0 to 5 VDCinput range) with a 24 VAC half-wave (rectifier) power supply. Set the staticpressure transducer range (using the SP range parameter) to one of the following:• (0): 0 in. W.C./0 Pa to 1.5 in. W.C./375 Pa• (1): 0 in. W.C./0 Pa to 2 in. W.C./500 Pa• (2): 0 in. W.C./0 Pa to 3 in. W.C./750 Pa• (3): 0 in. W.C./0 Pa to 4 in. W.C./1,000 Pa• (4): 0 in. W.C./0 Pa to 5 in. W.C./1,250 PaSet the static pressure transducer setpoint is using the Pressure parameter. Thedefault setpoint is 0.8 in. W.C./200 Pa, and is adjustable from 0 in. W.C./0 Pa to2 in. W.C./500 Pa in 0.1 in. W.C./25 Pa increments.The static pressure scale automatically changes from inches of water column(in. W.C.) to Pascals (Pa) when the Units parameter is changed from(Imp): Fahrenheit/in. W.C. to (Si): Celsius/Pa.Operation of the static pressure control loop depends on whether the fan isrunning. For proper operation of the static pressure control loop, the static pressurecontrol actuator must be installed properly. When the control signal is 0 VDC, thestatic pressure damper is fully closed with no air recirculating from the supply tothe return. Conversely, when the control signal is 10 VDC, the static pressuredamper is fully open with maximum air recirculating from the supply to the return.TEC Zoning Control System for Stand-Alone and BACnet® MS/TP Networked ApplicationsTechnical Bulletin41
Page 1 and 2: TEC Zoning Control System for Stand
Page 3 and 4: Sequence of Manual Status Display S
Page 5 and 6: TEC Zoning Control System for Stand
Page 7 and 8: Figure 1 illustrates a typical TEC
Page 9 and 10: Example: A typical installation may
Page 11 and 12: Bypass Damper Design RulesA bypass
Page 13 and 14: The zone controller automatically s
Page 15 and 16: Main User MenuUse the Main User Men
Page 17 and 18: Table 2: TEC2647Z-2 and TEC2647Z-2+
Page 23 and 24: Table 3: System Mode Calculation wi
Page 25 and 26: Table 6: Lockout Level Function Det
Page 27 and 28: - It is possible for an internal zo
Page 29 and 30: Table 9: Maximum Heat Flow Adjustme
Page 31 and 32: Note that 0 to 100% is directly con
Page 33 and 34: Table 12: TEC2664Z-2 Rooftop Contro
Page 37 and 38: The rooftop controller calculates t
Page 39: Rooftop Controller Heating and Cool
Page 43 and 44: PIR Occupancy Sensor LogicThe PIR o
Page 45 and 46: AO2HeatingSetpointCoolingSetpointAO
Page 47 and 48: HeatingSetpointCoolingSetpointB05AO
Page 49 and 50: The system mode can be set to eithe
Page 51 and 52: 1. The outdoor temperature displays
Page 53 and 54: FIG:byps_dmprSequence of OperationF
Page 55 and 56: • Properly set the Min Pos, Max P
Page 57 and 58: Table 19: Rooftop Controller Commis
Page 59 and 60: Table 22: Zone Controller Number (
Page 61 and 62: Table 23: TEC2647Z-2 and TEC2647Z-2
Page 65: Table 24: TEC2664Z-2 Rooftop Contro
Page 69 and 70: • Ground the circuit if required.
Page 71 and 72: Table 25: Troubleshooting Details 1
Page 73 and 74: Table 25: Troubleshooting Details 1

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