Hydraulic Components; Integral Expansion Vessel - Viessmann VITODENS 200-W Installation Instructions Manual

Vitoden 200-W installation
Hydraulic components in the boiler
Pump
The following figure shows the pump head that is available in excess of the hydraulic
resistance of the appliance.
Flow rate in l/h
Expansion vessel
The table shows the maximum system
volume that the integral expansion vessel
can sustain under different charge pressure
conditions. If the system volume exceeds
that shown, an additional expansion vessel
must be fitted and connected to the
heating system primary return pipe as
close as possible to the appliance. If an
extra vessel is required, ensure that the
total capacity of both vessels is adequate.
Vessel charge and initial system pressure
Total water content of system using 10
litre capacity expansion vessel supplied
with appliance
For systems having larger capacity,
multiply the total system capacity in litres
by the factor to obtain the total minimum
expansion vessel capacity required
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4/9/07 7:27 pm Page 32
Further details are available in the current
issues of BS 5449 and BS 6798.
Note
If the pressure gauge rises by 1.5 bar when
the appliance is at maximum temperature
with all radiators in circulation an extra
expansion vessel is required.
bar
psi
litres
gallons
0.5 0.75 1.0
7 ,3 10,9 14,5
136 125 103
30 27 22
0,08 0,097 0,11
1.5
21,8
71
15
0,16