York AFFINITY PT9 Technical Manual

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Contents

036-21581-001 Rev. B (0904)Unitary Products Group 5FILTER PERFORMANCEThe airflow capacity data published in the “Blower Perfor-mance” table listed above represents blower performanceWITHOUT filters. To determine the approximate blower per-formance of the system, apply the filter drop value for the fil-ter being used or select an appropriate value from the “FilterPerformance” table shown below.NOTE: The filter pressure drop values in the “Filter Perfor-mance” table shown below are typical values for the type offilter listed and should only be used as a guideline. Actualpressure drop ratings for each filter type vary between filtermanufacturer.APPLYING FILTER PRESSURE DROP TODETERMINE SYSTEM AIRFLOWTo determine the approximate airflow of the unit with a filter inplace, follow the steps below:1. Select the filter type.2. Select the number of return air openings or calculate thereturn opening size in square inches to determine theproper filter pressure drop.3. Determine the External System Static Pressure (ESP)without the filter.4. Select a filter pressure drop from the table based uponthe number of return air openings or return air openingsize and add to the ESP from Step 3 to determine thetotal system static.5. If total system static matches a ESP value in the airflowtable (i.e. 0.20, 0.60, etc,) the system airflow corre-sponds to the intersection of the ESP column and Model/Blower Speed row.6. If the total system static falls between ESP values in thetable (i.e. 0.58, 0.75, etc.), the static pressure may berounded to the nearest value in the table determining theairflow using Step 5 or calculate the airflow by using thefollowing example.Example: For a 120,000 Btuh furnace with 2 return openingsand operating on high speed blower, it is found that total sys-tem static is 0.58" w.c. To determine the system airflow, com-plete the following steps:1. Obtain the airflow values at 0.50" & 0.60" ESP.Airflow @ 0.50": 2285 CFMAirflow @ 0.60": 2175 CFM2. Subtract the airflow @ 0.50" from the airflow @ 0.60" toobtain airflow difference.2175 - 2285 = -110 CFM3. Subtract the total system static from 0.50" and divide thisdifference by the difference in ESP values in the table,0.60" - 0.50", to obtain a percentage.(0.58 - 0.50) / (0.60 - 0.50) = 0.84. Multiply percentage by airflow difference to obtain airflowreduction.(0.8) x (-110) = -885. Subract airflow reduction value to airflow @ 0.50" toobtain actual airflow @ 0.58" ESP.2288 - 88 = 2197FILTER PERFORMANCE - PRESSURE DROP INCHES W.C. AND (KPA)Airflow Range Minimum OpeningSizeFilter TypeDisposable WASHABLE FIBER* Pleated1 Opening 2 Openings 1 Opening 2 Opening 1 Opening 2 Opening 1 Opening 2 OpeningSq. in. Sq. in. In w.c. Pa In w.c. Pa In w.c. Pa In w.c. Pa In w.c. Pa In w.c. Pa0 - 750 230 0.01 2.5 0.01 2.5 0.15 37751 - 1000 330 0.04 10 0.03 7.5 0.20 501001 - 1250 330 0.08 20 0.07 17 0.20 501251 - 1500 330 0.08 20 0.07 17 0.25 621501 - 1750 380 658 0.14 35 0.08 20 0.13 32 0.06 15 0.30 75 0.17 421751 - 2000 380 658 0.17 42 0.09 22 0.15 37 0.07 17 0.30 75 0.17 422001 & Above 463 658 0.17 42 0.09 22 0.15 37 0.07 17 0.30 75 0.17 42

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