7
Fig. 6
ALTERNATIVE METHODS OF FILLING A SEALED SYSTEM
NOTES:
– When it is not possible to avoid a situation where the initial system pressure and static head are equal a manually
fitted top up container should be fitted as shown above.
Take note of the requirements relative to container capacity: height above system, inclusion of a non-return valve,
stop cock and automatic air vent in the feed pipe, as shown in fig. 5.
Note also the feed pipe connection is made to the heating return as close to the appliance as possible.
– The Local Water Undertaking MUST approve ALL connections between the system and a water storage cistern or
water main supplying D.H.W.
METHOD 1 (complies with BS6798.1987)
METHOD 2 (complies with BS6798.1987)
2.9.2 System volume (total water content)
The following table gives the maximum system volume that
the integral 7 l expansion vessel can sustain under different
charge pressure conditions.
If the system volume exceeds that shown, an additional
expansion vessel must be fitted and connected to the hea-
ting system primary return pipe as close as possible to the
appliance. If an extra vessel is required, ensure that the total
capacity of both vessels is adequate. Further details are avai-
lable in the current issues of BS5449 and BS6798.
NOTE: If the pressure gauge indicates 2.65 bar or grea-
ter when the appliance is at maximum temperature
with all radiators in circulation an extra expansion
vessel is required.
2.9.3 Pressure and temperature gauge
Separate pressure & temperature gauge are located on the
appliance facia panel.
2.9.4 Safety valve
A safety valve set at 3 bar (43.5 psi) is fitted to the applian-
ce and a discharge pipe is routed to outside of the applian-
ce. This discharge pipe should be extended to terminate
safely away from the appliance and where a discharge
would not cause damage to persons or property but would
be detected.
The pipe should be able to withstand boiling water, be a
minimum of 15 mm in diameter, and not include any hori-
zontal runs prone to freezing.
2.10
D.H.W. SYSTEMS
– The authority of the local Water Company should be
obtained before the appliance is connected to the cold
water mains supply. Check that the mains supply pressure
is within the prescribed limits (table 4). If necessary, a
pressure reducing valve should be fitted to the mains sup-
ply before the D.H.W. inlet connection.
– The final 600 mm (24 in) of the mains supply pipe to the
boiler must be copper.
– We recommend a maximum D.H.W. flow rate of 11 l/m
(2.4 gpm) for
“SUPER 90”
and 12 l/m (2.7 gpm) for
“SUPER 102”
. Higher flow rates will not damage the
Vessel charge and initial
system pressure
Total water content of system
using 7 l (1.54 gal) capacity
expansion vessel supplied
with appliance
For systems having a larger
capacity multiply the total
system capacity in litres (gal-
lons) by the factor to obtain
the total minimum expansion
vessel capacity required litres
(gallons)
bar
psi
l
gal
0.5
7.3
87
18.5
.0833
1.5
21.8
44
9.7
.156
1.0
14.5
64
14.0
.109
TABLE 8
