Flexit 111805, Руководство по установке

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Dimensioning pressure drop for shunt valves is the pressure drop in the circuit which has variable flow:
For 2-way valves the pressure drop over the battery dimensioning.
A guide to help choice of shuntvalves might be read off in respective water battery table.
For 3-way valves there is two options:
• Constant flow over battery
• Variable flow over battery
For waterbatteries, constant flow is preferable (see example connection A and B). Then there is always circulation
in the battery and it avoids that stagnant water freezes at low temperature. It has a circulating pump in the battery
circuit.
Since the water flow is constant, the pressure drop across the battery isn’t dimensioning in choice of shuntvalves. The
pressure drop before the valve, back towards the next point in the system at a constant pressure is dimensioning.
Since we do not have this information about the facilities we have chosen to provide the choice of 3-way valve with
valve authority at a given pressure drop see tables (pressure drop in the variable flow circuit). The pressure drop is
chosen as high as possible but with a about 50% valve authority. Guide for 3-way valves may therefore be seen as
examples that apply under given conditions. It is therefore important that the plumber check the choice of shuntval-
ves and make the necessary adjustment of the current facility.
The valve should be selected so the minimum is 50% valve authority. This is important for the valve to give any effect
when it regulates.
Valve authority: The pressure drop across the valve relative to both the pressure drop across the valve +
pressure drop in the flow circuit.
To obtain correct values, employ the Flexit
calculation application available at our home
page www.flexit.no
Dimensiondata from calculation of table.
Outside temperature -25 °C
Inside tempe 20 °C
These tables shows which valves our valve supplier Belimo recommends.
OBS! You should control this value against actual pressure drop in your sys-
tem.
For each shunt valve there is a K
VS
- value (capacityvalue in m 3 /h):
K
V
- Valvecoefficient given as water flow in m 3 /h, with a pressure drop over a
fully opened valve with 1 bar (100kPa) calculated.
K
VS
- The chosen valve K
V
value when valve is fully opened
General
m
3
/h K
V
= 36
TO»V
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