Baxi 47 075 35 Installation & Servicing Instructions Manual page 16

Fig. 5
6.6 Expansion Vessel (Central Heating only)
1. The appliance expansion vessel is pre­charged to 0.5 bar. Therefore, the minimum cold fill pressure is 0.5 bar. The vessel is
suitable for correct operation for system capacities up to 125 litres. For greater system capacities an additional expansion vessel
must be fitted. For GB refer to BS 7074 Pt 1. For IE, the current edition of I.S. 813 "Domestic Gas Installations".
6.7 Safety Pressure Relief Valve (Fig. 6)
1. The pressure relief valve is set at 3 bar, therefore all pipework, fittings, etc. should be suitable for pressures in excess of 3 bar and
temperature in excess of 100°C.
2. The pressure relief discharge pipe should be not less than 15mm dia, run continuously downward, and discharge outside the
building, preferably over a drain. It should be routed in such a manner that no hazard occurs to occupants or causes damage to
wiring or electrical components. The end of the pipe should terminate facing down and towards the wall.
3. The discharge must not be above a window, entrance or other public access. Consideration must be given to the possibility that
boiling water/steam could discharge from the pipe.
4. A remote relief valve kit is available to enable the boiler to be installed in cellars or similar locations below outside ground level (kit
no. 5121379).
Fig. 6
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6.8 Domestic Hot Water Circuit (Fig. 7)
1. All DHW circuits, connections, fittings, etc. should be fully in accordance with relevant standards and water supply regulations.