Baxi Main Combi 24 HE Installation And Service Instructions Manual page 12

Fig. 4
Fig. 5
Filling Loop
Pressure Relief Valve
12
© Baxi Heating UK Ltd 2011
Double
Stop
Stop
Check
Valve
Valve
Valve
Temporary
DHW
Hose
Mains
Inlet
Fig. 6
Discharge Pipe
6.0 System Details
6.5
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. 5) 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
CH
approved equipment.
Return
4. 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".
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
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. 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
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.
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).
System Filling and Pressurising
Expansion Vessel
(Central Heating only)
Safety Pressure Relief Valve (Fig. 6)