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INST
ALLA
TION
TECHNICAL INFORMATION
4.5 Hydraulic specifications
The hydraulic specifications represents the
pressure (available head for the central
heating system) as a function of the flow
rate.
Fig. 4.3
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
0,45
0,50
Pression (bar)
Flow (l/h)
The boiler load loss has already been re-
moved.
Flow rate with closed thermostatic
valves
The boiler is equipped with an automatic
by-pass, which protects the condensing pri-
mary exchanger.
In case of excessive reduction or total stop-
ping of water circulation in the heating plant
due to the closing of thermostatic valves or
circuit elements valves, by-pass ensures a
minimum water circulation inside the con-
densing primary exchanger.
The by-pass is calibrated to a differential
pressure of about 0.3-0.4 bar.
4.6 Expansion vessel
Note: this boiler is designed for opera-
tion only in a sealed central heating sys-
tem.
The height difference between the pressure
relief valve and the highest point in the sys-
tem may be 10m at most.
For greater differences, increase the pre-
load pressure in the expansion vessel and
the system, when cold, by 0.1 bar for each
additional 1m.
Fig. 4.4
Total capacity
l
7,0
Pre-load pressure
kPa
100
bar
1,0
Useful capacity
l
3,5
Maximum volume of water in
the system *
l
109
* Where conditions are:
• Average maximum temperature of the
system is 85 °C
• Initial temperature when filling up the sys-
tem is 10 °C
For systems with volumes
greater then the one indicated in
the above table, an additional
expansion vessel must be pro-
vided.
Содержание Activ A 25S
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