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• SELECTION EXAMPLE - MODEL BTC (BLOWER UNIT) <br /> `!IVD/NE <br /> Selection Example(Blower Unit) <br /> At this point we have a full model number of <br /> Selection Example Conditions(Blower Unit) BTC215AS8421NBAN <br /> Select a unit heater to meet the following conditions: 6.Determination of Transformer: <br /> 1. Heating output capacity= 195,000 Btu/Hr per design To operate the BTC215AS8421 NBAN on 230V/60Hz/3ph <br /> engineer supply voltage,we need to review Table 10.1 to determine if <br /> 2. External Static Pressure=0.2. any field installed transformers are required.The table <br /> 3. Internal Static Pressure=0.0. No static producing indicates that we need a 230V to 115V step down <br /> accessories are required at this point, but filters may be transformer for the power exhaust and gas control circuit <br /> added later. voltage.As indicated in the footnote for that table,Table 6.4 <br /> 4. Heat exchanger=Aluminized Steel directs us to the correct size for this model,which is 0.5kVA. <br /> Transformers for blower models are typically smaller than <br /> 5.Gas Type=Propane those used for propeller models,as the transformer is not <br /> 6.Gas Controls=Single-Stage needed for the blower motor. <br /> 7.Supply Voltage:230V/60Hz/3Ph <br /> 8.CFM=2,600 <br /> With the information listed above,the basic model, using the <br /> information in this catalog and the Model Nomenclature shown <br /> on page 19, can be selected as shown: <br /> 1.Determine the Model and Input Rating(MBH): <br /> Using the Heating output capacity,the Furnace Input Rating <br /> is determined from Table 6.1.The closest model to 195,000 <br /> Btu/Hr output has an Btu/Hr Input rating of 215,000 Btu/Hr so <br /> the Furnace Input Rating=215.The corresponding model <br /> for a 215 size, blower,separated combustion unit heater is <br /> BTC.The model and size are a BTC215. <br /> 2.Determination of Heat Exchanger Material: <br /> From item#4 in the example,the Heat Exchanger required <br /> is aluminized steel.Thus,the Heat Exchanger Material=A <br /> from the Model Nomenclature on page 19. <br /> 3.Determine the Ignition Type: <br /> The Ignition Type=S from the Model Nomenclature on page 19. <br /> 4.Determine Power Code Required: <br /> From page 9 we see that a unit requiring a static of 0.2 and a <br /> cfm of 2600 requires a 1 horsepower motor with a-275 drive <br /> that is turned open 3 turns. Referring to Table 7.1 it can be <br /> determined that for a BTC215 with a 1 HP motor and a-275 <br /> drive operating on 230V/60Hz/3Ph that it will have a power <br /> code=84. However, note that if filters are added later,that <br /> drive/motor combination will not be sufficient.One alternate <br /> drive selection could have been made with a 1 HP motor with <br /> a-276 drive.The power code would be 85. <br /> 5.Determine the control type: <br /> From items#5 and#6 in the example,the gas type is <br /> Propane Gas and controls are Single-Stage. From <br /> note©on page 4,we are directed to use Control Code <br /> (CC)=21. <br /> 14 6-170.7 <br />