hVac controls guide for Plans examiners and Building inspectors
hVac controls guide for Plans examiners and Building inspectors hVac controls guide for Plans examiners and Building inspectors
Figure 17: Economizer control sequenceAHU — 1 & 2 Automatic Dampers• Outside Air Damper○○○○○○○○ModulatingClosed when AHU is not operating.Controlled by space temperature, time of day, outside air temperature, and ventilation requirementEconomizer cycle:◗◗Operates when outside air temperature is
) Control strategyEconomizers must not be controlled only by mixed air temperature and must be able to be sequencedwith mechanical cooling equipment. ASHRAE provides an exception for systems controlled from spacetemperature, such as single zone systems.Code SectionsIECCASHRAE2009: NA 2007: 6.5.1.1.22012: 403.1.1.2 2010: 6.5.1.1.2c) High limit shutoffWhen increase in outdoor air will no longer reduce cooling energy use, economizers must be able toreduce outdoor air to the design minimum.Code SectionsIECCASHRAE2009: NA 2007: 6.5.1.1.32012: 403.3.1.1.3 2010: 6.5.1.1.3Hydronic SystemsThe requirements for hydronic systems mainly apply to buildings with a complex, built up HVAC design.However, the IECC includes some control requirements for large (>300,000 Btu/h) systems that arecategorized as simple systems. One example of such a system is a boiler loop that supplies hot water forradiant heating in a large apartment building. Such simple, but large hydronic systems are required to complywith the applicable hydronic system controls that are discussed in the next section of this guide.Additional Detail:Code SectionsIECCASHRAE2009: 503.3.2 2007: NA2012: 403.3.2 2010: NAPrescriptive Requirements for Simple Systems 25
- Page 2 and 3: ContentsIntroduction ..............
- Page 5 and 6: Commercial buildingControl requirem
- Page 7 and 8: Prescriptive requirementsfor Comple
- Page 9 and 10: Code Requirements andCompliance Che
- Page 11 and 12: Control Requirements for All System
- Page 13 and 14: Figure 4: Sample control sequence s
- Page 15 and 16: d) Automatic setback and shutdown c
- Page 17 and 18: Figure 9: VSD installed on a supply
- Page 19 and 20: Figure 13: Motorized damperFigure 1
- Page 21 and 22: Building InspectionSuggested Compli
- Page 23: 4) The supply of outside air is red
- Page 27 and 28: 4) The supply of outside air is red
- Page 29 and 30: must be positioned well down the du
- Page 31 and 32: Figure 23: BAS screen shot indicati
- Page 33 and 34: Code SectionsIECCASHRAE2009: NA 200
- Page 35 and 36: Figure 27: Illustrated control sequ
- Page 37 and 38: Code SectionsIECCASHRAE2009: 503.4.
- Page 39: Building InspectionSuggested Compli
- Page 42 and 43: Building InspectionSuggested Compli
- Page 44 and 45: Figure 38: Sample control sequence
- Page 46: Building Technology ProgramThe U.S.
Figure 17: Economizer control sequenceAHU — 1 & 2 Automatic Dampers• Outside Air Damper○○○○○○○○ModulatingClosed when AHU is not operating.Controlled by space temperature, time of day, outside air temperature, <strong>and</strong> ventilation requirementEconomizer cycle:◗◗Operates when outside air temperature is
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