Potterton Performa 28i Installation And Servicing Instructions page 12

Stop Valve
Fig. 4
Fig. 4a
Filling Loop
Pressure Relief Valve
Discharge Pipe
12
DHW
CH
Mains
Return
Inlet
Fig. 5
6.0 System Details
6.5
1. A filling point connection on the central heating
return pipework must be provided to facilitate
Double
initial filling and pressurising and also any
Check
subsequent water loss replacement/refilling.
Valve
2. The filling method adopted must be in
accordance with all relevant water supply bye-
laws and use approved equipment.
3. Your attention is drawn to: IRN 302 and Byelaw
14.
Temporary
Hose
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 (Fig. 4).
5. There are connection points on the mains cold
water inlet and central heating return isolation
taps (Fig. 4a) to which the optional Filling Loop Kit
(Pt. No. 248221) can be assembled.
6.6
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 80
litres. For greater system capacities an additional
expansion vessel must be fitted - refer to BS 7074
Pt 1.
6.7
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.
System Filling and Pressurising
Expansion Vessel
(Central Heating only)
Pressure Relief Valve (Fig. 5)