Potterton Performa System 12e, Installation And Servicing Instructions, Page: 13 / 44

6.0 System Details
13
6.4 System Filling and Pressurising
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.
2. The filling method adopted must be in
accordance with the Water Supply (Water
Fittings) regulations and the Water Bylaws
(Scotland).
3. Your attention is drawn to: Paragraph 24 of
Schedule 2 Section 8 of the publication Water
Regulations Guide which gives recommendations
and guidance on approved methods for filling
sealed systems.
4. The sealed primary circuits may be filled or
replenished by means of a temporary connection
between the primary circuit and a supply pipe
provided the arrangement in accordance with
Diagram R24.2a of the Water Regulations Guide.
5. The temporary hose must be completely
removed at both ends after use.
6.5 Expansion Vessel
1. The appliance expansion vessel is pre-charged
to 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 - refer to BS 7074
Pt 1.
6.6 Pressure Relief Valve (Fig. 4)
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.
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.
Fig. 3
Fig. 4
Stop
Valve
Double
Check
Valve
Mains
Cold
Water
CH
Return
Temporary
Hose
Pressure Relief Valve
Discharge Pipe
Stop
Valve