21 static resistances, 22 electric heat cfm limitations – York DY 048 User Manual

Page 19

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343615-YTG-B-0308

Johnson Controls Unitary Products

19

1. Deduct these resistance values from the available external static pressure shown in SUPPLY AIR BLOWER PERFORMANCE Tables.
2. Add these resistance values to the available static resistance values on SUPPLY AIR BLOWER PERFORMANCE Tables.
3. The pressure through the economizer is greater for 100% outdoor air than for 100% return air. If the resistance of the return air duct system is less than

0.25 IWG, the unit will deliver less CFM during full economizer operation.

TABLE 21: STATIC RESISTANCES

DESCRIPTION

RESISTANCE, IWG

CFM

1000

1200

1400

1600

1800

2000

2200

2400

2600

2800

3000

ECONOMIZER

1,3

0.07

0.08

0.09

0.11

0.13

0.15

0.17

0.20

0.23

0.26

0.30

ELECTRIC

HEATERS

1

7-15KW

0.04

0.05

0.06

0.07

0.08

0.10

0.12

0.14

0.16

0.19

0.22

20-30KW

0.06

0.07

0.08

0.09

0.11

0.13

0.15

0.17

0.20

0.23

0.26

COOLING ONLY

2

0.08

0.10

0.12

0.14

0.16

0.18

0.20

0.23

0.26

0.29

0.32

TABLE 22: ELECTRIC HEAT CFM LIMITATIONS

Size

(Tons)

Voltage

Minimum Supply Air (CFM)

Heater kW

5

7

10

15

20

30

3

208/230-1-60

900

900

900

900

900

-

208/230-3-60

900

900

900

900

900

-

460-3-60

-

900

900

900

900

-

600-3-60

-

-

900

900

900

-

4

208/230-1-60

1200

1200

1200

1200

1200

-

208/230-3-60

1200

1200

1200

1200

1200

-

460-3-60

-

1200

1200

1200

1200

-

600-3-60

-

-

1200

1200

1200

-

5

208/230-1-60

1500

1500

1500

1500

1500

1500

208/230-3-60

1500

1500

1500

1500

1500

1500

460-3-60

-

1500

1500

1500

1500

1500

600-3-60

-

-

1500

1500

1500

1500

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