17
Grant Vortex Outdoor Module
4 - GENERAL BOILER INFORMATION
See Fig. 10
Grant sealed system kits, incorporating circulating
pumps are available.
1 The boiler is only suitable for use with a sealed
system complying with the requirements of BS 5449.
The maximum temperature of the central heating
water is 80°C.
2 The system must be provided with the following
items:-
a Diaphragm expansion vessel complying with
BS 4814.
b Pressure gauge.
c Safety valve.
d Approved method for filling the system.
Refer to BS 7074:1 for further guidance.
3 The expansion vessel can be fitted in either the
return or flow pipework in any of the
recommended positions as shown in Fig. 10. To
reduce the operating temperature of the expansion
vessel diaphragm, position it below the pipe to
which it is connected. The expansion vessel may
be positioned away from the system, providing the
connecting pipe is not less than 13 mm diameter.
Sealed systems
4.13
4 The pressure gauge should have an operating range
of 0 to 4 bar.
5 The safety valve, set to operate at 2.5 bar, should
be fitted in the flow pipework near to the boiler.
The pipework between the safety valve and boiler
must be unrestricted, i.e. no valves. The safety
valve should be connected to a discharge pipe
which will allow the discharge to be seen, but
cannot cause injury to persons or property.
6 Provision should be made to replace water lost
from the system. This can be done manually. A
double check valve assembly must be used.
7 An automatic air vent should be fitted to the
highest point of the system.
8 All fittings used in the system must be able to
withstand pressures up to 3 bar.
9 Radiator valves must comply with the requirements
of BS 2767(10):1972.
10 One or more drain taps (to BS 2879) must be used
to allow the system to be completely drained.
11 For proprietary expansion vessel/valve/gauge
packs, refer to the manufacturers instructions for
the correct location on the heating system.
Fig. 10 - Sealed system
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