York ZV Series Installation Manual

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5370598-BIM-C-051836 Johnson Controls Ducted SystemsBelt TensionThe tension on the belt should be adjusted as shown in Figure 26.Figure 26: Belt AdjustmentCFM Static Pressure and Power-Altitude and TemperatureCorrectionsThe information below should be used to assist in application ofproduct when being applied at altitudes at or exceeding 1000feet above sea level.The air flow rates listed in the standard blower performancetables are based on standard air at sea level. As the altitude ortemperature increases, the density of air decreases. In order touse the indoor blower tables for high altitude applications,certain corrections are necessary.A centrifugal fan is a "constant volume" device. This meansthat, if the rpm remains constant, the CFM delivered is thesame regardless of the density of the air. However, since the airat high altitude is less dense, less static pressure will begenerated and less power will be required than a similarapplication at sea level. Air density correction factors are shownin Table 16 and Figure 27.AAABSPAN LENGTHDEFL. FORCEC** NEVER LOOSENProcedure for adjusting belt tension:1. Loosen six nuts (top and bottom) A.2. Adjust by turning (B).3. Never loosen nuts (C).4. Use belt tension checker to apply a perpendicularforce to one belt at the midpoint of the span asshown. Deflection distance of 4mm (5/32”) isobtained.To determine the deflection distance from normalposition, use a straight edge from sheave to sheave asreference line. The recommended deflection force is asfollows:Tension new belts at the max. deflection forcerecommended for the belt section. Check the belttension at least two times during the first 24 hours ofoperation. Any retensioning should fall between the min.and max. deflection force values.5. After adjusting re-tighten nuts (A).Table 16: Altitude/Temperature Correction FactorsAirTemp.Altitude (Ft.)0 1000 2000 3000 4000 5000 6000 7000 8000 9000 1000040 1.060 1.022 0.986 0.950 0.916 0.882 0.849 0.818 0.788 0.758 0.72950 1.039 1.002 0.966 0.931 0.898 0.864 0.832 0.802 0.772 0.743 0.71560 1.019 0.982 0.948 0.913 0.880 0.848 0.816 0.787 0.757 0.729 0.70170 1.000 0.964 0.930 0.896 0.864 0.832 0.801 0.772 0.743 0.715 0.68880 0.982 0.947 0.913 0.880 0.848 0.817 0.787 0.758 0.730 0.702 0.67690 0.964 0.929 0.897 0.864 0.833 0.802 0.772 0.744 0.716 0.689 0.663100 0.946 0.912 0.880 0.848 0.817 0.787 0.758 0.730 0.703 0.676 0.651