574B Corner Weights, Selection Procedure with Example

574B CORNER WEIGHTS

4x 3

CORNER #	024	030	036	042	048	060

1	70		78		92	100

2	54		60		72	78

3	84		94		111	120

4	141		156		188	201

TOTAL WEIGHT	350		388		463	499

SELECTION PROCEDURE (WITH EXAMPLE)

I DETERMINE COOLING AND HEATING REQUIREMENTS

AT DESIGN CONDITIONS:
Given:
Required Cooling Capacity (TC)	34,500 Btuh
Sensible Heat Capacity (SHC)	26,000 Btuh
Required Heating Capacity	60,000 Btuh
Condenser Entering Air Temperature	95°F
Indoor-Air Temperature	80°F edb 67°F ewb
Evaporator Air Quantity	1200 CFM
External Static Pressure	0.2 in. wg
Electrical Characteristics	230-1-60

IISELECT UNIT BASED ON REQUIRED COOLING CAPACITY.

Enter Net Cooling Capacities table at condenser entering temperature of 95 F. Unit 036 at 1225 cfm and 67 F ewb (entering wet bulb) will provide a total capacity of 36,500 Btuh and a SHC of 27,600 Btuh. Calculate SHC correction, if required, using Note 4 under Cooling Capacities tables.

IIISELECT HEATING CAPACITY OF UNIT TO PROVIDE DESIGN CONDITION REQUIREMENT.

In the Heating Capacities and Efficiencies table on page 4, note that the unit 036090 will provide 70,000 Btuh with an input of 90,000 Btuh.

IV DETERMINE FAN SPEED AND POWER REQUIRE- MENTS AT DESIGN CONDITIONS.

Before entering the air delivery tables, calculate the total static pressure required. From the given example, the Wet Coil Pressure Drop Table, and the Filter Pressure Drop table on page 16, find at 1200 cfm:

Wet Coil Pressure Drop	0.032 in. ws
External Static Pressure		0.2 in. wg
Filter Pressure Drop		0.13 in. wg
Total Static Pressure
		0.362 in. wg

Enter the table for Dry Coil Air Delivery — Horizontal and Downflow Discharge. At 0.362 ESP (external static pressure), the fan will deliver 1235 cfm with the NOM Speed pin selected.

VSELECT UNIT THAT CORRESPONDS TO POWER SOURCE AVAILABLE.

The Electrical Data table shows that the unit is designed to operate at 208/230-1-60.

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