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Variable Air Volume for Rooftop Units Application Guide (Form 5515846

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Variable Air Volume for Rooftop Units Application Guide (Form 5515846 APPLICATION GUIDE Variable Air Volume for Rooftop Units Form 5515846-YAD-A-1119 Variable Air Volume for Rooftop Units Application Guide | 5515846-YAD-A-1119 Table Of Contents Introduction .................................................................5 Thermostatic Expansion Valve (TXV) .....33 Rooftop Unit (RTU) .....................................................5 Electronic Expansion Valve (EXV) .........33 Matching RTU Capacity to the Load ...........................6 Hot Gas Reheat (HGRH) ........................34 Constant Volume (CV) and Single Zone VAV Hot Gas Bypass (HGBP) ........................37 (SZVAV) Systems ..............................................7 Variable Speed Compressors (VSC) ver- Operational Sequence ..............................7 sus Staged Compressors .......................38 Benefits of SZVAV ....................................8 Fans and Airflow ..............................................38 VAV Systems ..............................................................9 Fan Laws ................................................39 VAV Terminal Unit ............................................10 Multiple Fans ..........................................41 Airflow Measurement ..............................10 VAV Fan Turndown .................................41 VAV Dual Duct Applications .............................17 Direct Drive Plenum Fans ......................42 Pressure Independent Decks .................17 Ventilation ........................................................42 CV Separate Dampers ...........................18 Energy Recovery Wheels (ERW) ...........42 Zone Control ...........................................19 Dampers .................................................47 Acoustical Concepts ...............................20 Unit Construction and Accessories ..................49 Quiet Design – General Recommenda- Humidifiers .............................................49 tions ........................................................20 Coil Coating ............................................51 VAV Terminal Unit Types .................................22 Shaft Grounding .....................................52 Single Duct VAV .....................................22 Vibration Isolation ...................................52 Dual Duct VAV ........................................23 Phase Monitor ........................................52 Parallel Fan Powered VAV .....................24 Air Blenders ............................................52 Series Fan Powered Terminal Units .......25 Gas-Fired Heating Modules ...................54 Underfloor ........................................................26 Cabinet Construction Double Wall..........55 Controls ....................................................................27 Hot Water and Steam Coils ....................55 Morning Warm-Up ...........................................27 Codes and Standards ...............................................56 Occupied ................................................27 Energy – Department of Energy (DOE) ............... 56 Schedule ................................................27 Energy Efficiency – ANSI/ASHRAE/IESNA Optimal Start ..........................................27 Standard 90.1 ..................................................56 Static Pressure (SP) Reset .............................27 Energy Efficiency ....................................57 Exhaust Air (EA) System .................................28 Mandatory Requirements .......................59 Modulating Exhaust Fan .........................28 Prescriptive Requirements .....................61 Modulating Exhaust Damper With Fan ...28 Energy Efficiency – Title 24 .............................63 External Control ......................................28 Ventilation Basics ...................................63 Return Air (RA) System ...................................28 Regulatory Requirements .......................64 Return Fan Discharge Pressure .............28 Economizer Fault Detection and Supply Fan Airflow Tracking ...................28 Diagnostics (FDD) ..................................64 Economizer Control .........................................28 Selecting a Unit in Selection Navigator to Changeover Method ...............................29 Meet Title 24 ...........................................65 Dry Bulb ..................................................29 Ventilation – ANSI/ASHRAE Standard 62.1 ....65 Single Enthalpy ......................................29 Ventilation Challenges ............................65 Dual Enthalpy .........................................29 Ventilation Air Distribution .......................66 Auto ........................................................29 Ventilation Rates ....................................66 Independent Twinning .....................................29 Drain Pans ..............................................66 Components and Operation .....................................31 Wind and Seismic – ASCE/SEI 7-16 ...............66 Refrigeration ....................................................31 Wind Standards ......................................66 Pressure Transducers ............................32 Seismic Standards .................................70 Multiple Cooling Stages ..........................32 Site Class ...............................................71 Anchorage ..............................................72 2 YORK 5515846-YAD-A-1119 | Variable Air Volume for Rooftop Units Application Guide Table Of Contents (Continued) Green Buildings – ANSI/ASHRAE/USGBC/ Service......................................................................84 IES Standard 189.1 .........................................73 Start-Up Wizard ...............................................84 ANSI/ASHRAE/IESNA Standard 90.1 and Fault Diagnostics Detection (FDD) ..................84 ANSI/ASHRAE/USGBC/IES Standard Access Doors ..................................................85 189.1 .....................................................73 Lights ...............................................................85 Purpose and Scope of ANSI/ASHRAE/US- Variable Frequency Drive (VFD) Bypass .........85 GBC/IES Standard 189.1 .......................73 Condenser Roof Safety Tie-Off .......................86 Mandatory Requirements .......................74 Convenience Outlet .........................................86 Prescriptive Requirements .....................76 Serviceable Filter Driers ..................................86 Performance – AHRI Standard 340/360 ..........77 Isolation Valves................................................87 Safety – IEC 60335-1 and IEC 60335-2-40 .....78 Condenser Cleaning Hatch .............................88 Consortium for Energy Efficiency (CEE) .........79 Mobile Access Portal (MAP) ............................88 Canadian Standards Association (CSA) ..........79 Standard and High End User Interface ...........89 Installation ................................................................79 Dirty Filter Transducers ...................................89 RTU Installation ...............................................79 Grease Lines ...................................................89 Rigging and Lifting the RTU ...................79 Belt Guards .....................................................90 Rooftop Curbs ........................................80 Fan Inlet Guards ..............................................90 Short Circuit Current Rating ...................81 Condensate Overflow Switch ..........................90 Multipiece Construction ..........................81 Maintenance ....................................................91 Dual Point Power ....................................82 Performance ....................................................92 Post Shipment Documentation ...............82 Glossary ...................................................................93 VAV Installation ................................................83 References .............................................94 Duct Connections ...................................83 Operation ................................................83 List Of Tables TABLE 1: Single Duct VAV Box Fan Types .............................................................................................................15 TABLE 2: Parallel and Series Fan Status per Mode of Operation ..........................................................................15 TABLE 3: Free Cooling Sensor Requirements .......................................................................................................29 TABLE 4: 150 Ton Staging ......................................................................................................................................32 TABLE 5: Leakage Classification per AMCA Standard 511 ....................................................................................49 TABLE 6: Air Blender Application Summary ...........................................................................................................53 TABLE 7: Electrically Operated Unitary Air Conditioners and Condensing Units – Minimum Efficiency Requirements .........................................................................................................................................58 TABLE 8: Maximum Damper Leakage (CFM/sq. ft at 1 iwg) ����������������������������������������������������������������������������������58 TABLE 9: IEER Efficiency Improvement Values Required
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