See Figs. 6 and 15.
7b.1
The appliance is supplied suitable for connection to a
sealed system. If it is to be used with an open vent system then
the instructions given below must be followed.
7b.2
A 22mm pre-formed combined feed and vent pipe available
as an optional extra must be connected to the appliance. See
Section 11.3 and Fig.15.
Note:
Refer to Section 3 - Table 5, for the sizes of the flow and
return pipework.
7b.3
The feed and expansion cistern should be arranged so that
a minimum static head of 1.0m above the top of the
7b. Open Vent Primary System
10
8.1
The final 600mm of the mains cold water connection to the
appliance should be made in copper tube only.
8.2
The appliance is suitable for a mains pressure of up to 10 bar.
8.3
The appliance is fitted with a mains supply isolating valve. A
pressure reducing valve should be fitted if necessary.
8.4
The maximum hot water flow rate, via the flow regulator, is
nominally 18 l/m ±15% .
8.5
In winter, when the mains inlet water temperature is lower a
reduced flow rate, achieved at the tap, will increase the required
delivery temperature.
8.6
Hot and cold taps and mixing valves used with this
appliance must be suitable for operating at the available mains
pressure and up to 65°C.
8.7
Anti-syphonage arrangements are normally not necessary
except for some loose-head showers. See paragraph 8.10 following.
8.8
Thermostatically controlled shower valves will guard against
the flow of water at too high a temperature.
8.10
The head of a loose head shower must not fall closer than
25mm above the top edge of the bath to prevent its immersion
in bath water. Alternatively the shower must be fitted with an
anti-syphonage device at the point of the flexible hose
connections.
8. Domestic Water Supply
8.11
The supply of hot and cold mains water direct to a bidet is
permitted, subject to local Water Company requirements,
provided that the bidet is of the over-rim flushing type. The
outlet(s) should be shrouded and unable to have any temporary
hand held spray attached. No anti-syphonage arrangements are
necessary.
8.12
As the maximum temperature of the hot water heat
exchanger is limited by the control circuit, there is normally no
need for water treatment to prevent scale accumulation. In
exceptional circumstances a device to prevent scale formation
can be fitted.
8.13
Installation of a scale inhibitor assembly should be in
accordance with the requirements of the local Water Company.
An isolating valve to allow servicing should be fitted.
8.14
The temporary water hardness can be determined using a
standard test paper or by reference to the local water company.
8.15
A miniature expansion vessel (Zilmet R
1
/
2
, 160ml, 15bar),
available as an optional extra, should be fitted into the domestic
water supply circuit if there is evidence of water hammer.
8.16 A mini-expansion vessel must also be fitted if a back-
flow prevention device or a water meter has been fitted to the
cold water mains supply.
appliance or above the highest point in the heating circuit,
whichever is the highest, is achieved. See Fig. 6.
8.4
The feed and vent pipe must rise continuously from the
appliance to the feed and expansion cistern.
8.5
A safety valve is not required on an open vented system.
If the safety valve is left in position then a pipe must be fitted
which terminates such that any discharge does not cause a
hazard to the occupants or damage to electrical components.
8.6
Air within the appliance will be expelled via the feed and
vent connection or dissipated into the rest of the system which
must be fitted with manual air vents at any high points.
8.7
The pump is set to maximum and must not be reset.
Hot Water
Out
Mains Cold
Water
Lockshield Valve
Radiator Valve
Heating Flow
Heating
Return
22mm dia. Vent Pipe
Circulating Pump
Combined feed and vent
pipe (22mm).
Must rise continuously.
British Standard Stop Valve.
Fixed spindle type
Water Main
NOTE:
A Drain Cock should be
installed at the lowest point of the
heating circuit and beneath the
appliance.
STATIC HEAD (S.H.)
Minimum Static Head 1.0m (3ft). Measured
from the top surface of the appliance or the
highest point in the heating system to the
water level in the feed and expansion tank.
Appliance
(Refer to
Fig. 1 for
appliance
Water Flow
diagram)
Part view showing
Vent Pipe connection
Fig. 7. Open vent water system.
S.H.
Disconnect the flexible hose from behind the
circulating pump. The expansion vessel and
flexible hose are not required in the open vent
system and may be discarded. Fit the 22mm
vent pipe supplied as on optional extra.
Summary of Contents for Highflow 400 BF
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