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

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Heating and Cooling Weight Zone SelectionFor any system to operate properly, carefully determine which zones drive thesystem and their weight for demand calculations. The recommendations includedin Table 8 are provided as a general rule, and should be re-evaluated on a per-jobbasis depending on the specifics of the system design and layout.Table 8: Recommended Initial Number of Voting Zones with WeightTotal Number ofZones in the SystemSystem Layout1 to 5 All Internal or External Zones 1 to 33 to 5 Mix and Match of Internal and 2 to 3External Zones6 or More 1Mix and Match of Internal andExternal ZonesRecommended Initial Numberof Voting Zones with Weight3 to 81. Choose a practical number of zones per rooftop controller, to allow comfort in all zones.Consider the following when selecting voting zones:• Not all zones in the system need to be voting zones. Generally, anywhere froma third to half of the total number of zones in the system should be votingzones.• For larger installations where internal zones (zones not exposed to an outsidewall) are included in the system, there should be a ratio of approximately fourexternal voting zones for every one internal voting zone.• Zones selected as voting zones for demand calculations should represent:- areas that are exposed to the highest peak heating and cooling loads.- areas that include a significant portion of the equipment peak load capacity.For example, if a system has five zones where one of the zones representshalf of the peak load capacity, that zone should be selected as a votingzone.- areas that are subject to momentary spikes in occupancy (if those zones areexpected to respond during increased occupancy periods). Typicalexamples include conference rooms, cafeterias, or other common areas.• Selecting a voting zone that is either undersized or commissioned withoperational flaws and errors may result in erratic system behavior due toadding total demand that cannot be met.Consider the following regarding weight parameter values of the voting zones:• Internal zones do not affect the heating demand calculation; instead, they onlyaffect the cooling demand calculation. Internal zones typically call for coolingduring occupied periods, even during the winter months. If the internal zonesever call for heating, then it is certain that the surrounding external zones arealready in the heating mode.26TEC Zoning Control System for Stand-Alone and BACnet® MS/TP Networked ApplicationsTechnical Bulletin
- It is possible for an internal zone to be slightly overcooled during peaksummer cooling loads. This situation happens when the rooftop controllersupplies its maximum cooling capacity, and when the volume of cold airdetermined by the minimum position of the zone damper during occupiedperiods is already providing too much cooling capacity to the internal zone.- It is also possible for an internal zone to be slightly overheated during peakwinter heating loads. This situation happens when the rooftop controllersupplies its maximum heating capacity; and when the volume of hot airdetermined by the minimum position of the zone damper during occupiedperiods is already providing too much heat, for which the internal zonesrarely need.• External zones considered to be of primary importance should have both theirheating and cooling weight set to 100%.• Zones considered to be of secondary importance may have their weight set to alesser value than 100%, to reflect the importance they have in the total votingdemand calculations.• Some zones (for example, an office surrounded by panoramic windows) mayexperience problematic behavior while in their peak heating or cooling mode,due to location, design, and/or degree of exposure. These problematic zonescan have their peak load demand satisfied; however, this usually results inhigher energy costs since some of the other zones in the system are slightlyoverheated or overcooled. The installer is responsible for properly identifyingthese problematic areas and determining if they should be fully satisfied (at acertain energy expense) or if they should be left unsatisfied during specificpeak load periods, to reduce energy consumption and for the greater good ofthe rest of the zones in the system.- Adding many voting zones (including problematic areas) to a rooftopcontroller provides greater occupancy comfort at higher energy costs.- Restricting the number of voting zones (including problematic areas) to arooftop controller provides energy savings at the expense of occupancycomfort in some of the zones in the system.Minimum, Maximum, and Heat Flow AdjustmentsAlthough system balancing can be accomplished using configuration settingswithin the zone controller, we recommend installing a balancing damper at thebalancing side takeoff of all zones. A balancing damper reduces excessive airflowand the noise that goes with it, if the zones and/or associated ductwork areoversized.Minimum Position Adjustment (Min Pos Parameter)This parameter sets the minimum position of the zone damper to deliver theminimum amount of air to the zone in all conditions. When powered up, thedamper never closes below the minimum position setting.TEC Zoning Control System for Stand-Alone and BACnet® MS/TP Networked ApplicationsTechnical Bulletin27
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: Table 6: Lockout Level Function Det
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 and 40: Rooftop Controller Heating and Cool
Page 41 and 42: Typically, the number of rooftop co
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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