User Manual

25
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Symbols
3-port valve, control path with equal-percentage valve characteristic, bypass with linear valve characteristic.
3-port valve, control path with equal-percentage valve characteristic, bypass with linear valve characteristic with 70% of the k
VS
value.
This compensates for the ow resistance of the heat exchanger, so that the total volumetric ow ⩒
100
remains as constant as possible.
2-port valve, control path with equal-percentage valve characteristic.
2-port valve or 6-port control ball valve in the respective control path with linear valve characteristic.
3-port, control path and bypass with linear valve characteristic. Bypass with 70% of the k
vs
value.
This compensates for the ow resistance of the heat exchanger, so that the total ow amount ⩒
100
remains as constant as possible.
3-port valve, control path and bypass with linear valve characteristic.
3-port valve, control path and bypass with equal-percentage valve characteristic.
Denitions
Abbr. Term Unit Denition
Δp Differential pressure kPa Pressure differential between plant sections.
Δp
max
Maximum differential
pressure
kPa
Maximum permissible differential pressure across the valve’s control path (when mixing),
valid for the entire actuating range of the motorized valve.
Δp
maxV
Maximum differential
pressure
kPa
Maximum permissible differential pressure across the valve’s control path (when distributing),
valid for the entire actuating range of the motorized valve.
Δp
min
Minimum differential pressure kPa
Minimum differential pressure required, so that the differential pressure regulator works
reliably with combi valves. ∆p
min
depends on presetting position, see data sheet for details.
Δp
V0
kPa Maximum differential pressure across the valve’s closed control path.
Δp
V100
Differential pressure at
nominal ow rate
kPa Differential pressure across the fully open valve and the valve’s control path by a volumetric ow ⩒
100
.
Δp
s
Closing pressure kPa
For 2-port valves, maximum permissible differential pressure at which the motorized valve
will close securely against the pressure (close off pressure). Only valid for 2-port valves.
Δp
MV
kPa
Differential pressure across the variable ow path. Often Δp
MV
is not known,
in which case typical values can be used.
Δp
VR
kPa Differential pressure between ow and return.
ΔT Temperature spread K Temperature differential between ow and return.
DN Nominal size Characteristic for matching parts of the piping system.
H
0
Shutoff head m The head generated by a pump at closed value, at a given speed and a given pump medium.
H
100
Valve fully open Stroke of fully open valve.
kPa Druckeinheit kPa 100 kPa = 1 bar = 10 mWS.
mWC Meter water column m
k
V
Nominal ow m³/h
Amount of cold water (5…30 °C) passing through the valve at the respective stroke
and at a differential pressure of 100 kPa (1 bar).
k
VS
Nominal ow rate m³/h
Nominal ow rate of cold water (5...30 °C) through the fully open valve (H
100
) at a differential
pressure of 100 kPa (1 bar).
Spring return function Shutoff in the event of a power failure.
PN PN class
Characteristic relating to the combination of mechanical and dimensional properties
of a component in the piping system.
PS PS class Maximum allowable pressure.
P
v
Valve authority
Ratio of differential pressure across fully open valve (H
100
) and differential pressure across
valve and variable ow path. To ensure control, a minimum valve authority of 0.25 is required.
PV ≥ 0.5 is recommended for good controllability.
Q
100
Rated capacity kW Plant’s design capacity.
⩒
100
Volumetric ow m³/h Volumetric ow with valve fully open
(H
100
).
⩒
min
Minimum volumetric ow m³/h
Smallest presettable volumetric ow through the fully open combi valve (H
100
).
c Specic heat capacity kJ/kgK
r
Specic density kg/m³