Hydraulic Specifications; Expansion Vessel - Biasi M300V.2025 SM User Manual And Installation Instructions

4.3

Hydraulic specifications

The hydraulic specifications represents the
pressure (available head for the central
heating system) as a function of the flow
rate.
Model M300V.2025 SM
Pressure (bar)
0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500
Fig. 4.3
Model M300V.2530 SM - M300V.3035 SM
Pressure (bar)
0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1450 1500
Fig. 4.4
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
stopping of water circulation in the heating
system due to the closing of thermostatic
TECHNICAL INFORMATION
Flow rate (l/h)
Flow rate (l/h)
valves or circuit elements valves, the by-
pass ensures a minimum water circulation
inside the condensing primary exchanger.
The by-pass is calibrated to a differential
pressure of about 0.3-0.4 bar.
4.4

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 10 m 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 1 m.
Total capacity
Pre-load pressure
Useful capacity
Maximum volume of water in
the system *
Fig. 4.5
* 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
greater then the one indicated in
the above table, an additional
expansion vessel must be pro-
vided.
l 7,0
kPa 100
bar 1,0
l 3,5
l 109
with volumes
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