Trane AM4A0A18S11SA Series, Installation, Operation And Maintenance Manual

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116 CLCH-SVX07C-EN
Start-Up
Field-obtained factors can provide maximum accuracy. To obtain the factor in the field, measure
the differential pressure output from the transmitter while measuring the airflow through the
system. Once these two values have been measured, simply solve for K using the following
equation:
Fan Size (inches)/Type Fan Class Fan Name K-Factor
32 FC Class I 32 FA 20400.0
32 FC Class II 32 FB 20150.0
36 FC Class I 36 FA 28049.9
36 FC Class II 36 FB 27549.0
40 FC Class I 40 FA 39236.4
40 FC Class II 40 FB 38067.7
10 BC belt-drive plenum Class I or II 10 PA or 10 PB 563.0
11 BC belt-drive plenum Class I or II 11PA or 11 PB 703.0
12 AF belt-drive plenum Class I or II 12PA or 12 PB 1168.7
14 AF belt-drive plenum Class I or II 14PA or 14 PB 1536.1
16 AF belt-drive plenum Class I or II 16PA or 16 PB 1870.
18 AF belt-drive plenum Class I or II 18PA or 18 PB 2270.7
20 AF belt-drive plenum Class I or II 20PA or 20 PB 2905.2
22 AF belt-drive plenum Class I or II 22PA or 22 PB 3673.2
25 AF belt-drive plenum Class I or II 25PA or 25 PB 4608.2
28 AF belt-drive plenum Class I or II 28 PA or 28 PB 6277.8
32 AF belt-drive plenum Class I or II 32 PA or 32 PB 7847.3
36 AF belt-drive plenum Class I or II 36 PA or 36 PB 10017.8
40 AF belt-drive plenum Class I or II 40 PA or 40 PB 13023.1
44 AF belt-drive plenum Class I or II 44 PA or 44 PB 14692.8
49 AF belt-drive plenum Class I or II 49 PA or 49 PB 18299.2
55 AF belt-drive plenum Class I or II 55 PA or 55 PB 23901.0
63 AF belt-drive plenum Class I or II 63 PA or 63 PB 31135.0
10.5 AF direct-drive plenum Class II 10 NF or 10 NW 630
13.5 AF direct-drive plenum Class II 13 NR or 13 NF 952
15 AF direct-drive plenum Class II 15 NR or 15 NF 1139
18 AF direct-drive plenum Class II 18 NR or 18 NF 1673
20 AF direct-drive plenum Class II 20 NR or 20 NF 1942
22 AF direct-drive plenum Class II 22 NR, 22 NF, or 22 NW 2454
24 AF direct-drive plenum Class II 24 NR, 24 NF, or 24 NW 3010
27 AF direct-drive plenum Class II 27 NR or 27 NF 3701
30 AF direct-drive plenum Class II 30 NR or 30 NF 4620
22 AF stacked direct-drive plenum Class II 22 SF or 22 SW 2849
24.5 AF stacked direct-drive plenum Class II 24 SF or 24 SW 4765
Note:
(1) to be used for fan rpm < 700 or cfm < 25,500. (2) to be used for fan rpm > 700 or cfm > 25,500
K = ACFM/SQRT(DP)
Where:
K = Field-provided constant factor.
ACFM = Actual airflow (ft
3
/min.) being measured at the air density being measured.
DP = Differential pressure (inches w.g.) being measured by the transmitter.
Table 32. Constant K Factors