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2.2 System Pressure
When the appliance is connected to a sealed central heating system, the system pressure
should be checked periodically by means of the pressure gauge at the expansion vessel (see
Figure 4). The WS18 appliance comes complete with an integrated expansion vessel, pressure
gauge and filling loop. The minimum pressure, as indicated by the black needle, must not be
less than 0.5 bar when the appliance is cold and typically around 2.5 bar when the appliance is
at normal operating temperature. If the pressure is outside this range contact Warmflow or your
installer.
System Pressure = 0bar System Pressure = 1bar
2.3 System Filling
After the system has been properly filled the pressure gauge should read 1 bar when the
system is cold (refer to the image on the right in Figure 4). The valve must be fully closed and
the flexible filling loop removed from the valve in accordance with building regulations. Expect a
small water loss from the pipe.
At filling or re-filling of the system, special attention must be given to the concentration of
corrosion inhibitors in the system water. Where there is a need for topping up, concentrations
must be restored to inhibitor manufacturers’ recommendations and monitored going forward.
Frequent or routine topping up of the system should not be necessary and may prove harmful to
the appliance. Should topping up prove necessary on a frequent or routine basis you must
contact Warmflow or your installer.
For further information refer to Section 3.2 Sealed Systems (see page 38).
Figure 4: Reading System Pressure.
