c) The appliance is equipped with an inter-
nal by-pass that operates with system
heads (H) greater than 3 m. The maxi-
mum flow through the by-pass is about
300 l/h. If thermostatic radiator valves
are to be installed, at least one radiator
should be without a thermostatic valve
(usually the bathroom radiator).
d) A sealed system must only be filled by a
competent person using one of the
approved methods shown in fig. 4/b.
The system design should incorporate
the connections appropriate to one of
these methods.
Fitted to the base of the boiler is a ana-
logue pressure gauge, see fig 18/a
page 25.
Ensure that the syst em is filled t o
between 1 and 1.2 bar after all the radi-
ators are vented.
2.4
CHARACTERISTICS
OF FEEDWATER
– All recirculatory systems will be subject
to corrosion unless an appropriate
water treatment is applied. This means
that the efficiency of the system will
deteriorate as corrosion sludge accu-
mulates within the system, risking dam-
age to pump and valves, boiler noise
and circulation problems.
– For optimum performance after installa-
tion this boiler and its associated central
heating sys t em mus t be f lushed in
accordance with the guidelines given in
BS 7593 “Treatment of water in domes-
tic hot water central heating systems”.
– This must involve the use of a propri-
etary cleanser, Sime Ltd recommend
only the use of Fernox products for the
flushing and final treatment of the sys-
tem water. artificially softened water
must not be used to fill the heating sys-
tem.
Failure to flush and add inhibitor to
the system may invalidate the appli-
ance warranty.
– It is important to check the inhibitor
concentration after installation, system
modification and at every service in
accordance with the manufacturer’s
instructions. (Test kits are available
from inhibitor stockists).
2.5
COAXIAL DUCT ø 60/100
The standard air inlet, smoke outlet assem-
bly is part number 8096250, and is sup-
plied complete with mounting instructions.
NOTE: Ensure that any accessories are
suitable for condensing boilers.
2.5.1
Coaxial flue diaphragm
The boilers
"25 HE -EV/SYSTEM 25 HE -
EV"
are supplied of series with diaphragm
ø 87.5 to mount like indicated in figure (fig.
4/c).
ATTENTION: the diaphragm should be
used only when the length of the coaxial
duct is below 1,5 m (only for “25 HE -EV”
and “SYSTEM 25 HE -EV” models).
2.5.2
Coaxial duct accessories
The accessories to be used for this type of instal-
lation and some of the connecting systems that
may be adopted are illustrated in fig. 5.
With the bend included in the kit, the max-
imum length of the flue should not exceed
5.0 meter (25 HE -EV/SYSTEM 25 HE -
EV) - 2.5 meter (30 HE -EV). When the ver-
tical extension code 8086950 is used, the
terminal part of the pipe must always
come out horizontally
.
2.6
COAXIAL DUCT
ø 80/125
(only for “30 HE -EV”)
The air inle t-smoke outle t assembl y ø
80/125 is supplied in a kit code 8096253
complete with mounting instructions.
With the pipe bend included in the kit, the
maximum length of the piping should not
exceed 5.0 meter.
The diagrams in fig. 5 illustrate a number of
examples of dif fer ent coaxial outlets ø
80/125.
2.7
KIT ø 60/100 PLUME
CODE 8096260
A special kit code 8096260 is supplied for
this purpose (see fig. 5/a).
2.8
POSITIONING THE
OUTLET TERMINALS
The outlet terminals for forced-draught
appliances may be located in the external
perimeter walls of the building.
To provide some indications of possible solu-
tions,
Table 4
gives the minimum distances
to be observed, with reference to the type
of building shown in fig. 6.
12
ONLY FOR “25 HE -EV” AND “SYSTEM 25 HE -EV” MODELS
Fig. 4/c
ALTERNATIVE METHODS OF FILLING A SEALED SYSTEM
Fig. 4/b
