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6.0 System Details
13
6.5 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. There are connection points on the mains cold water
inlet and central heating return isolating taps (Fig. 6) to
which the optional filling loop kit (Part No. 248221) can
be assembled.
3. The filling method adopted must be in accordance
with all relevant water supply regulations and use
approved equipment.
4. Your attention is drawn to: for GB: Guidance G24.2
and recommendation R24.2 of Water Regulations
Guide. for IE: the current edition of I.S. 813 “Domestic
Gas Installations”.
5. 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.
6.6 Expansion Vessel
(Central Heating only)
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. For GB
refer to BS 7074 Pt 1. For IE, the current edition of
I.S. 813 “Domestic Gas Installations”.
6.7 Pressure Relief Valve (Fig. 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.
Fig. 7
Stop
Valve
Double
Check
Valve
DHW
Mains
Inlet
CH
Return
Temporary
Hose
Pressure Relief Valve
Filling Loop
Discharge Pipe
Fig. 5
Fig. 6
Stop
Valve