Potthof & Co 33kw System Filling and Pressurising Fig, Expansion Vessel Central Heating only

Stop	Double
	Check
Valve
	Valve
DHW	Temporary
	Hose
Mains
Inlet

Fig. 4

Stop

Valve

CH Return

6.0System Details

6.5System Filling and Pressurising (Fig. 4)

1.A filling point connection on the central heating return pipework must be provided to facilitate initial filling and pressurising and also any subsequent water loss replacement/refilling.

A filling loop & instructions are provided with the boiler

2.The filling method adopted must be in accordance with all relevant water supply regulations and use approved equipment.

3.Your attention is drawn to:

for GB: Guidance G24.2 and recommendation R24.2 of the Water Regulations Guide.

for IE: the current edition of I.S. 813 “Domestic Gas Installations”.

4.The sealed primary circuits may be filled or replenished by means of a temporary connection between the circuit and a supply pipe, provided a ‘Listed’ double check valve or some other no less effective backflow prevention device is permanently connected at the inlet to the circuit and the temporary connection is removed after use.

6.6Expansion Vessel (Central Heating only)

Filling Loop

Fig. 5

Fig. 6

Pressure Relief Valve

Discharge Pipe

1.The appliance expansion vessel is pre-charged 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 (24, 28 models) 155 litres (33 models). 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”.

6.7Safety 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).

© Baxi Heating UK Ltd 2012 13