Product Overview

Data sheet STV Series
Balancing Valves
VDDNB122 © Danfoss 05/08
STV /
STVL
Number of Turns
Size 1 2 3 4 5 6 7 8 9 10
1/2” 0.21 0.37 0.52 0.72 1.00 1.36 1.88 2.96 3.65 4.12
Cv Values
3/4” 0.39 0.70 0.96 1.31 1.80 2.44 3.36 4.47 5.22 5.92
1” 0.56 0.89 1.19 1.74 2.67 4.18 5.80 7.54 9.16 10.20
1-1/4” 0.92 1.53 2.09 3.13 4.76 6.84 9.05 11.30 13.30 15.20
1-1/2” 1.39 2.38 3.25 4.76 7.19 10.3 13.90 17.10 19.80 22.60
2” 2.32 4.18 6.03 8.82 13.80 19.4 24.60 29.00 33.20 36.50
STVA Number of Turns
Size 1 2 3 4 5 6 7 8 9 10
2-1/2” 3.2 5.9 11.1 23.2 41.2 59.2 76.6 91.1 101.0 108.0
Cv Values
3” 6.4 11.0 15.7 21.5 34.2 56.8 79.5 98.6 114.0 128.0
4” 9.3 15.7 22.0 38.3 77.7 115.0 145.0 174.0 197.0 220.0
5” 11.6 25.5 38.3 73.1 123.0 174.0 225.0 274.0 317.0 349.0
6” 20.9 38.3 78.9 151.0 216.0 285.0 341.0 394.0 447.0 493.0
STVC Number of Turns
Size 2 3 4 5 6 7 8 9 10 11 12 14 16 18
8”
46 66 84 139 215 290 365 452 545 638 696 - - -
Cv Values
10” 116 160 204 349 494 689 884 1031 1177 1291 1405 - - -
12” 116 180 244 396 546 708 869 1012 1153 1290 1427 1588 1668 1764
Setting Flow Coefficient
values
(Cv value = gpm@1psi ∆P):
Based upon the flow or differential pressures
required within the system, the flow can be
determined by using the equation:
Q = flow
C
v
= flow coefficient
∆p

= differential pressure
For correction of fluids other than water,
the following equation applies provided
the viscosity of the fluid is the same for
water, which is the case for most glycol and
brine solutions:
Q
R
= real flow
Q
M
= measured flow
 = specific density of fluid
Q = C
v
.
√
_____
∆p
Q
M
√
___

Q
R
=
Installation:
Install the balancing valve with the arrow on the
valve’s body pointing in the direction of the flow
in the system.
To ensure an accurate reading, a straight length
of 5 times the diameter of the pipe should be
piped prior to the valve and a straight length
of at least 2 times the pipe diameter should be
piped after the valve.
If a pump is installed near the valve, a straight
length of 10 times the diameter of the pipe
should be piped prior to the valve to reduce an
inaccurate measurement due to turbulence.
3