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7
SELECTION PROCEDURE
To determine combination ratings for 569D/F, 576C and 566D/E
units matched with 524A Series air handlers, follow these steps:
I DETERMINE COOLING LOAD, EVAPORATOR-AIR
TEMPERATURE, AND QUANTITY.
Given:
Total Cooling Capacity
Required(TC)......................127,000Btuh
Sensible Heat Capacity
Required(SHC)..................... 95,000Btuh
CompressorType ...........................Scroll
Temperature Air Entering Condenser (Edb). . . . . . . . 95 F
Temperature Air Entering
Evaporator(db/wb)................80Fdb,67Fwb
EvaporatorAirQuantity...................4,000cfm
ExternalStaticPressure ..................0.4in.wg
Length of Interconnecting
RefrigerantPiping ...................25ft(Linear)
PowerSupply(V-Ph-Hz) ............... 208/230-3-60
II SELECT CONDENSING UNIT AIR-HANDLER
COMBINATION.
For this example, select a 569D120 matched with a
524A-C120 with high-capacity 4-row coil This 569D120/
524A-C120 condensing unit air-handler combination
provides 130,000 Btuh of total cooling capacity and
98,200 Btuh of sensible capacity at the given conditions. If
other temperatures or airflow values are required, interpo-
late the values from the combination ratings.
III DETERMINE SIZES OF LIQUID AND SUCTION LINES.
Enter Refrigerant Piping Sizes table. The sizes shown are
based on an equivalent length of pipe. This equivalent
length is equal to the linear length of pipe indicated at the
top of each sizing column, plus a 50% allowance for fitting
losses. (For a more accurate determination of actual
equivalent length in place of using the estimated 50%
value, refer to a standard refrigeration piping practice.) For
this example, note in the linear length column that the
proper pipe size is
1
/
2
in. for the liquid line and 1
3
/
8
in. for
the suction line.
IV DETERMINE FAN RPM AND BHP (BRAKE
HORSEPOWER).
At the Air Handler Fan Performance table enter at 524A-
C120 with high capacity coil at 4000 cfm and move to the
External Static Pressure (ESP) column. Note that the con-
ditions require 803 rpm at 1.77 bhp.
V DETERMINE MOTOR AND DRIVE.
Enter the Fan Motor Data tables and find the standard
motor for 524A-C120 unit rated at 2.4 Hp. Since the bhp
required is 1.77, a standard motor satisfies the require-
ment and should be used.
Next, find the type of drive that satisfies the 803 rpm
requirement in the Drive Data tables. For the 524A-C120
unit, the Standard Drive table on shows an rpm range of
666-863. Since the rpm required is 803, the standard drive
satisfies the requirement and should be used. Select the
standard motor and standard drive combination (option
code GC or ED).