Selection procedure (with example)
I Determine cooling and heating requirements at
design conditions:
Given:
Required Cooling Capacity (TC) ......34,000 Btuh
Sensible Heat Capacity (SHC) .......24,000 Btuh
Required Heating Capacity ..........60,000 Btuh
Condenser Entering-Air Temperature ........95F
Indoor-Air Temperature .......80Fedb, 67 F ewb
Evaporator-Air Quantity ...............1200 cfm
External Static Pressure ...............0.2in.wg
Electrical Characteristics (V-Ph-Hz) .......208-1-60
II Select unit based on required cooling capacity.
Enter Cooling Capacities table at condenser entering
temperature of 95 F. Unit 48SS036 at 1200 cfm and
67 F ewb (entering wet bulb) will provide a total ca-
pacity of 36,000 Btuh and an SHC of 26,200 Btuh.
Calculate SHC correction, if required, using Note 4
under Cooling Capacities tables.
III Select heating capacity of unit to provide design
condition requirement.
In the Heating Capacities and Efficiencies table on
page 5, note that unit 48SS036080 will provide
64,800 Btuh with an input of 80,000 Btuh.
IV Determine fan speed and power requirements
at design conditions.
Before entering the air delivery tables, calculate the
total static pressure required. From the given, the Wet
Coil Pressure Drop table, and the Filter Pressure Drop
table on page 18, find at 1200 cfm:
External static pressure 0.20 in. wg
Wet coil 0.088 in. wg
Filter 0.13 in. wg
Total static pressure 0.42 in. wg (rounded)
Enter the table for Dry Coil Air Delivery — Horizontal
Discharge for 230 and 460 V on page 16. For 208 v
operation, deduct 10% from value given. The fan will
deliver 1233 cfm at 0.4 external static pressure (1370
x 0.9) at high speed and 852 cfm at 0.5 external static
pressure (946 x 0.9) at low speed. The fan speed should
be set at high to satisfy job requirements.
V Select unit that corresponds to power source
available.
The Electrical Data table on page 24 shows that the
unit is designed to operate at 208-1-60.
MANUAL OUTDOOR AIR DAMPER FILTER RACKS AND FILTERS
ACCESSORY PART NUMBER ‘‘A’’
FILTER
RACK
CPFILTRK001A00 21
11
⁄
16
Љ
CPFILTRK002A00 31
11
⁄
16
Љ
CPFILTRK003A00 25
11
⁄
16
Љ
13
