SELECTION PROCEDURE

1.Determine cooling and heating requirements at design conditions.

Example:

 

Total cooling capacity ............

43,600 BTUH [12.78 kW]

Sensible cooling capacity ......

34,000 BTUH [9.96 kW]

Condenser entering air ..........

95°F [35°C]

Evaporator entering air ..........

63°F [17°C] wb/76°F [24°C] db

Indoor air flow ........................

1600 CFM [755 L/s]

External static pressure ..........

1.1 in wg

Required efficiency ................

13 SEER

2. Select unit to meet cooling requirements.

Since total cooling is within the range of 4 ton [14.07 kW] unit and requires 13 SEER efficiency level, enter cooling performance table, at 95°F [35°C] outdoor temperature, 63°F [17°C] wb entering indoor air, and 1600 CFM [755 L/s]:

Total capacity ..........................

46,700 BTUH [13.68 kW]

Power input ............................

3.3 kW

And also, at 76°F [24°C] db indoor entering air, and using the formula at the bottom of the page:

Sensible capacity....................

33,710 BTUH [9.87 kW]

UNIT DIMENSIONS—RJNA- SERIES

3. Determine blower speed and power to meet the system

requirements.

 

At the given external static pressure of 1.1 in wg, the belt model

must be selected. Enter the belt drive blower performance table

at 1600 CFM [755 L/s] and 1.1 in wg ESP:

RPM ..................

1205

Watts ..................

725

Drive ..................

M

4.Calculate indoor blower BTUH heat effect. BTUH = Watts x 3.413 = 2474

5.Calculate net cooling capacities.

Net total cooling = 46,700 – 2474 = 44,226 BTUH [12.96 kW] Net sensible cooling = 33,716 – 2474 = 31.242 BTUH [9.16 kW]

WEIGHTS

Accessory

Shipping—lbs [kg]

Operating—lbs [kg]

Economizer

142

[64]

130

[59]

Power Exhaust

30 Est. [13]

25 Est. [11]

Horizontal Economizer

90

[41]

80

[36]

Fresh Air Damper (Manual)

11

[5]

9

[4]

Fresh Air Damper (Motorized)

13

[6]

11

[5]

Roof Curb 8"

84

[38]

80

[36]

Roof Curb 14"

92

[42]

88

[40]

Roof Curb 24"

108

[49]

104

[47]

CENTER OF GRAVITY (C.G.)

Capacity Tons [kW]

 

A in. [mm]

B in. [mm]

3-5 [10.6-17.6]

 

381/4 [972]

253/4 [654]

 

 

 

 

 

 

Capacity Tons [kW]

Corner Weights by Percentage

 

 

A

B

C

D

3-5 [10.6-17.6]

23%

27%

23%

27%

[ ] Designates Metric Conversions

*Allow 57” for economizer on duct side.

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