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
