Johnson Controls J15 warranty Altitude Correction Factors

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CFM, STATIC PRESSURE, AND POWER - ALTI- TUDE AND TEMPERATURE CORRECTIONS

The information below should be used to assist in application of product when being applied at altitudes at or exceeding 1000 feet above sea level.

The air flow rates listed in the standard blower performance tables are based on standard air at sea level. As the altitude or temperature increases, the density of air decreases. In

349687-JTG-A-1007

order to use the indoor blower tables for high altitude applica- tions, certain corrections are necessary.

A centrifugal fan is a "constant volume" device. This means that, if the rpm remains constant, the CFM delivered is the same regardless of the density of the air. However, since the air at high altitude is less dense, less static pressure will be generated and less power will be required than a similar application at sea level. Air density correction factors are shown in Table 8 and Figure 2.

TABLE 8: ALTITUDE CORRECTION FACTORS

AIR TEMP

 

 

 

 

ALTITUDE (FEET)

 

 

 

 

 

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

 

40

1.060

1.022

0.986

0.950

0.916

0.882

0.849

0.818

0.788

0.758

0.729

50

1.039

1.002

0.966

0.931

0.898

0.864

0.832

0.802

0.772

0.743

0.715

60

1.019

0.982

0.948

0.913

0.880

0.848

0.816

0.787

0.757

0.729

0.701

70

1.000

0.964

0.930

0.896

0.864

0.832

0.801

0.772

0.743

0.715

0.688

80

0.982

0.947

0.913

0.880

0.848

0.817

0.787

0.758

0.730

0.702

0.676

90

0.964

0.929

0.897

0.864

0.833

0.802

0.772

0.744

0.716

0.689

0.663

100

0.946

0.912

0.880

0.848

0.817

0.787

0.758

0.730

0.703

0.676

0.651

The examples below will assist in determining the airflow per- formance of the product at altitude.

Example 1: What are the corrected CFM, static pressure, and BHP at an elevation of 5,000 ft. if the blower performance data is 6,000 CFM, 1.5 IWC and 4.0 BHP?

Solution: At an elevation of 5,000 ft the indoor blower will still deliver 6,000 CFM if the rpm is unchanged. However, Table 8 must be used to determine the static pressure and BHP. Since no temperature data is given, we will assume an air temperature of 70°F. Table 8 shows the correction factor to be 0.832.

Corrected static pressure = 1.5 x 0.832 = 1.248 IWC

Corrected BHP = 4.0 x 0.832 = 3.328

Example 2: A system, located at 5,000 feet of elevation, is to deliver 6,000 CFM at a static pressure of 1.5". Use the unit

blower tables to select the blower speed and the BHP requirement.

Solution: As in the example above, no temperature informa- tion is given so 70°F is assumed.

The 1.5" static pressure given is at an elevation of 5,000 ft. The first step is to convert this static pressure to equivalent sea level conditions.

Sea level static pressure = 1.5 / .832 = 1.80"

Enter the blower table at 6000 sCFM and static pressure of 1.8". The rpm listed will be the same rpm needed at 5,000 ft.

Suppose that the corresponding BHP listed in the table is 3.2. This value must be corrected for elevation.

BHP at 5,000 ft = 3.2 x .832 = 2.66

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Johnson Controls Unitary Products

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Contents DESCRIPTION SERIES SINGLE PACKAGE GAS/ELECTRIC UNITSAND SINGLE PACKAGE AIR CONDITIONERS TECHNICAL GUIDELIST OF TABLES TABLE OF CONTENTSLIST OF FIGURES J15 D J N24 A 2 A AA 1 0 1 2 4 A PRODUCT NOMENCLATURE15-25Ton Series 20 Model Number Nomenclature FEATURES FACTORY-INSTALLEDOPTIONS FIGURE 1 - UNIT CUTAWAY349687-JTG-A-1007 FIELD-INSTALLEDACCESSORIES CONTROL OPTIONS349687-JTG-A-1007 TABLE 3 GAS HEAT RATIINGS TABLE 1 SOUND POWER RATING1TABLE 2 CAPACITY RATINGS - ARI TABLE 4 COOLING CAPACITIES FOR J15DJ TABLE 5 COOLING CAPACITIES FOR J18DJ TABLE 6 COOLING CAPACITIES FOR J20DJ TABLE 7 COOLING CAPACITIES FOR J25DJ TABLE 8 ALTITUDE CORRECTION FACTORS FIGURE 2 - ALTITUDE/TEMPERATURE CONVERSION FACTOR Johnson Controls Unitary Products230/460/575 208 VOLT AND STANDARD DRIVE208 VOLT AND HIGH STATIC DRIVE VOLT ANDDRIVE 208 VOLT ANDSTANDARD 208 VOLT AND230/460/575 208 VOLT AND STANDARD DRIVE208 VOLT AND HIGH STATIC DRIVE VOLT AND230/460/575 208 VOLT AND STANDARD DRIVE208 VOLT AND HIGH STATIC DRIVE VOLT ANDDRIVE 208 VOLT ANDSTANDARD 208 VOLT AND230/460/575 208 VOLT AND STANDARD DRIVE208 VOLT AND HIGH STATIC DRIVE VOLT AND230/460/575 208 VOLT AND STANDARD DRIVE208 VOLT AND HIGH STATIC DRIVE VOLT ANDTABLE 17 STATIC RESISTANCES1 TABLE 18 POWER EXHAUST PERFORMANCETABLE 16 BLOWER MOTOR AND DRIVE DATA COMPRESSORS NOTE 1 HACR Type per NEC Johnson Controls Unitary Products349687-JTG-A-1007 NOTE 1 HACR Type per NECNOTE 1 HACR Type per NEC Johnson Controls Unitary ProductsMODELS TABLE 21 J**DJ VOLTAGE LIMITATIONS1TABLE 22 PHYSICAL DATA J15DJTABLE 24 ELECTRIC HEAT CORRECTION FACTORS TABLE 23 SUPPLY FAN VFD WEIGHTS, IN LBSFIGURE 3 - TYPICAL J**DJ FIELD WIRING DIAGRAM HOLE FIGURE 4 - FRONT VIEW DIMENSIONSTABLE 25 UTILITIES ENTRY DATA USED FORField Accessories for Side FIGURE 5 - REAR VIEW DIMENSIONSDimensions listed are for side duct flange openings seeTABLE 26 MINIMUM CLEARANCES ROOF JACK INSTALLATION ROOF CURB INSTALLATION FIGURE 7 - UNIT CENTER OF GRAVITYFIGURE 8 - TYPICAL UNIT APPLICATIONS SLAB ON GROUND INSTALLATIONTotal FIGURE 9 - FOUR AND SIX POINT LOADSTABLE 27 FOUR AND SIX POINT LOADS 4 Point Loads lbsFIGURE 12 - CUT AWAY OF ROOF CURB FIGURE 10 - UNIT ROOF CURB DIMENSIONSFIGURE 11 - ROOF CURB DUCT OPENINGS DIMENSION Page DESCRIPTION GUIDE SPECIFICATIONSGENERAL UNIT CONTROLS OUTDOOR CONDENSER FAN ASSEMBLYREFRIGERANT COMPONENTS GAS HEATING SECTION J**DJN MODELSELECTRICAL REQUIREMENTS UNIT OPERATING CHARACTERISTICSELECTRIC HEATING J**DJC/E MODELS STANDARD LIMITED WARRANTIESOTHER PRE-ENGINEEREDACCESSORIES AVAILABLE