Brochure

We reserve the right to alter information without notice.
Dimensioning
Selecting the right valve in an installation requires
some data about the system.
P pump available differential pressure from
pump
P load differential pressure for circulation
P STVP pressure drop over valve fully open
(diagram)
P PVM pressure drop over the PVM valve
(diagram)
Example:
Calculated value for a valve is 6.34 gpm.
7.25 psi is available differential pressure for
circulation P load 2.9 psi is required for the main.
for the PVM valve to achieve minimum working
pressure in the diagram.
Two valves can deliver 6.34 gpm 1” and 1 1/4”.
C 5044
DN 25
PN 20
H
P
L
Last
P+
P-
Pf
C 5044
DN 25
PN 20
P
Last
P
Pump
P
STV
P
PVM
cv-value the STV valve
Number 1/2” 3/4” 1” 1 1/4” 1 1/2” 2”
of turns
1 0.21 0.39 0.55 0.91 1.39 2.31
2 0.37 0.69 0.89 1.53 2.37 4.16
3 0.52 0.96 1.19 2.08 3.24 6.01
4 0.72 1.31 1.73 3.12 4.74 8.79
5 0.99 1.79 2.66 4.74 7.17 13.76
6 1.35 2.43 4.16 6.82 10.29 19.31
7 1.87 3.35 5.78 9.02 13.87 24.51
8 2.95 4.45 7.51 11.21 16.99 28.90
9 3.64 5.20 9.13 13.30 19.77 33.06
10 4.10 5.90 10.17 15.14 22.54 36.42
Adjustment and measuring
When adjusting, the differential pressure on the
PVM valve is measured and adjusted to 10 kPa.
At least one radiator valve needs to be slightly
open.
and a measuringtool. To be able to measure the
have a higher differential pressure over the STV
valve. Note that the differential pressure over the
STV valve will not be to high so that the min dif-
ferential pressure over the PVM valve will be to
low and the PVM valve stop to regulate. After the
again.
Optimising pump pressure
Lowering to minimum possible pump differential
pressure is carried out by measuring at the PVM
valve and obtaining at least 1.91 psi, this is the
pump’s lowest level at which the PVM can be
regulated.
Tunstall Corporation
118 Exchange Street Chicopee, MA 01013
Phone: [phone] Fax: [phone]
www.tunstall-inc.com
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March 2014