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SELECTION PROCEDURE
Combination ratings for 569J* units matched with 524J Series air handlers are in this book. If unit is used with an air handler, use the Bryant Electronic Catalog AHU
I. Determine cooling load,
Given:
Total Cooling Capacity
Required (TC) . . . . . . . . . . . . . . . . . . . 121,000 Btuh
Sensible Heat Capacity
Required (SHC) . . . . . . . . . . . . . . . . . . . 95,000 Btuh Compressor Type . . . . . . . . . . . . . . . . . . . . . . . . . Scroll
Temperature Air Entering
Condenser (Edb) . . . . . . . . . . . . . . . . . . . . . . . . . 95_F
Temperature Air Entering
Evaporator (db/wb) . . . . . . . . . . . . 80_F db, 67_F wb Evaporator Air Quantity . . . . . . . . . . . . . . . . . 4,000 cfm External Static Pressure . . . . . . . . . . . . . . . . . 0.4 in. wg
Length of Interconnecting
Refrigerant Piping . . . . . . . . . . . . . . . . . 25 ft (Linear) Power Supply
II.Select condensing unit air-handler combination.
For this example, select a 569J*12 matched with a 524J012 coil. This 569J*12/524J12 condensing unit
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 Bryant System Design Manual.) For this example, note in the linear length column that the proper pipe size is 1/2 in. for the liquid line and 13/8 in. for the suction line.
For extended line lengths over 100 feet, contact your Bryant representative or application engineer.
IV. Determine fan rpm and bhp (brake horsepower).
Refer to the 524J Air Handler Catalog - Fan Performance table. Enter the Air Handler Fan Performance table at 524J12 at 4000 cfm and move to the External Static Pressure (ESP) column. Note that the conditions require 803 rpm at 1.77 bhp.
V.Determine motor and drive.
Enter the Fan Motor Data tables and find the standard motor for 524J12 unit rated at 2.4 Hp. Since the bhp required is 1.77, a standard motor satisfies the requirement and should be used.
Next, find the type of drive that satisfies the 803 rpm requirement in the Drive Data tables. For the 524J012 unit, the Standard Drive table shows an rpm range of
CONTROLS
Operating sequences
When the wall thermostat calls for cooling, terminals G and Y1 are energized. As a result, the indoor fan contactor (IFC) and the compressor contactor (C1) are energized, causing the indoor fan motor (IFM), compressor #1, and outdoor fans (OFM) to start. The
If the unit has 2 stages of cooling, the wall thermostat will additionally energize Y2. The Y2 signal will energize compressor contactor #2 (C2), causing compressor #2 to start.
Regardless of the number of stages, the
When cooling demand decrease, the thermostat will
When cooling demand has been satisfied, the thermostat will
The outdoor fan motors (OFM) will turn off and
569J
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