Central Heating System - Viessmann VITODENS 200 WB2A Installation & Servicing Instructions Manual

3 Installation Requirements

3.5 Central Heating System

PUMP
The available head shown in figure 3/F is that in excess of the appliance hydraulic resistance,
i.e that available for the system.
EXPANSION VESSEL
The table below 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. Further details are available in the
current issues of BS 5449 and BS 6798.
Note: If the pressure gauge indicates 2.5 bar or greater when the appliance is at maximum
temperature with all radiators in circulation an extra expansion vessel is required.
PRESSURE GAUGE
A pressure gauge is situated on the appliance control panel. This can be viewed by lowering
the plastic panel cover.
PRESSURE RELIEF VALVE
A pressure relief valve set at 3 bar (43.5 psi) is supplied with the appliance.
Expansion Vessel Requirements (In accordance with BS 5449)
Vessel charge and initial system pressure
Total water content of system using
10 litre (2.2 gal) capacity expansion vessel
supplied with appliance
For systems having larger capacity, multiply
the total system capacity in litres (Gallons)
by the factor to obtain the total minimum
expansion vessel capacity required
Supplied By www.heating spares.co Tel. 0161 620 6677
bar 0.5
psi 7.3
litres 106
gallons 23
0.0833
18
1.0 1.5
14.5 21.5
75 42
16.5 9
0.11 0.16