User Guide

F-24390-2 © Copyright 2008 TAC All Rights Reserved. 7
Steam Two-position
Two-position zone valves and direct radiation valves are normally sized using a minimum of
10% of inlet pressure (psig).
Proportional
Proportional control valves are normally sized using:
• For low pressure (15 psig or less), use ΔP of 80% of gauge inlet pressure.
• For steam pressures greater than 15 psig, use ΔP of 42% of absolute (gauge plus 14.7)
inlet pressure.
• When the C
v
required is between two valve sizes, select the larger size. Do not size
steam valves using a pressure drop greater than 42% of the absolute inlet pressure.
Steam Capacity
See Table-6 for steam capacity of VB-7273 series valves.
Table-6 Steam Capacity in Pounds Per Hour for VB-7273 Series.
Valve Body
Part Number
C
v
Rating
Differential Pressure (ΔP in psi)
a
a
Values are for saturated steam (K = 1). Left column under each inlet pressure is for two-position control, and right column is for proportional control.
2 psig Inlet 5 psig Inlet 10 psig Inlet 15 psig Inlet 20 psig Inlet 25 psig Inlet
0.2 1.6 0.5 4 1 8 1.5 12 2 14 2.5 16
VB-7273-0-4-1 0.4 2.2 5.9 3.7 9.5 5.8 14 7.8 18 9.7 20 12 23
VB-7273-0-4-2 1.3 7.1 19 12 31 19 45 25 57 32 66 38 76
VB-7273-0-4-3 2.2 12322052327643965311264129
VB-7273-0-4-4 4.4 24 65 41 105 64 153 86 192 107 225 127 257
VB-7273-0-4-5 5.5 30 81 51 131 80 191 107 240 133 281 159 321
VB-7273-0-4-6 7.5 41 111 70 178 110 260 146 328 182 383 217 438
VB-7273-0-4-7 10 55 147 93 238 146 347 195 437 243 511 289 584
VB-7273-0-4-8 12 65 177 112 285 175 416 234 525 291 613 347 701
VB-7273-0-4-9 20 109 295 186 475 292 694 390 874 485 1021 579 1168
VB-7273-0-4-10 28 153 413 260 666 409 971 546 1224 679 1430 810 1636
VB-7273-0-4-11 40 218 590 372 951 584 1387 780 1749 970 2043 1157 2337
Valve Body
Part Number
C
v
Rating
Differential Pressure (ΔP in psi)
a
30 psig Inlet 35 psig Inlet 40 psig Inlet 50 psig Inlet 75 psig Inlet 100 psig Inlet
3 18 3.5 20 4 22 5 27 7.5 37 10 48
VB-7273-0-4-1 0.4 153116321732213830533968
VB-7273-0-4-2 1.3 49 100 52 103 56 105 67 124 97 172 126 221
VB-7273-0-4-3 2.2 82 170 88 174 94 177 114 211 164 291 214 373
VB-7273-0-4-4 4.4 164 339 177 348 188 354 228 421 328 583 427 747
VB-7273-0-4-5 5.5 205 424 221 435 235 443 285 526 410 729 534 934
VB-7273-0-4-6 7.5 280 578 301 593 320 603 389 718 559 994 728 1273
VB-7273-0-4-7 10 374 771 402 790 427 805 518 957 745 1325 971 1697
VB-7273-0-4-8 12 403 789 458 877 513 966 622 1149 894 1590 1165 2037
VB-7273-0-4-9 20 747 1542 803 1581 854 1609 1037 1914 1490 2649 1941 3395
VB-7273-0-4-10 28 939 1841 1068 2047 1196 2253 1451 2680 2086 3709 2718 4753
VB-7273-0-4-11 40 1494 3084 1606 3161 1709 3219 2073 3829 2980 5299 3883 6790