Supplied By www.heating spares.co Tel. 0161 620 6677
f)
The following paragraphs outline the specifications of the items
fitted to the appliances.
PUMP -
The available pump head shown in Figure 6 is that in excess of
the appliance hydraulic resistance, i.e. that available for the system.
1
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
2
3
4
5
6
7
Flow Rate ltr/min
Pump Head (m
H
2
0)
6
AVAILABLE PUMP HEADS
SBX 30 & CBX 38
CBX 32
CBX 24
EXPANSION VESSEL -
The integral expansion vessel is pre-charged to
a pressure of between 0.5 and 1.0 bar. This should be checked before
the water system is filled. Details below show the water system volume
that is acceptable for this vessel. If the system water volume is larger
then an additional vessel must be fitted to the system. BS 5449 and BS
6798 give further details regarding expansion vessel sizing and sealed
systems.
Vessel charge and
bar
0.5
0.75
1.0
1.5
initial system pressure
Total water content of system
using 8 L (1.54 gal) capacity
L
96
84
73
50
expansion vessel supplied
with appliance.
For systems having a larger
capacity multiply the total
system capacity in litres
(gallons) by these factors to
0.0833 0.093
0.109 0.156
obtain the total minimum
expansion vessel
capacity required in litres.
Expansion Vessel Requirements
PRESSURE GAUGE -
A pressure gauge is situated on the appliance
control panel. This can be viewed by lowering the bottom front panel.
PRESSURE RELIEF VALVE -
A pressure relief valve set to 3 bar (43.5 psi)
is supplied with the appliance, however it will start to open at
approximately 2.7 bar. It should not be used to flush the system.
FILLING LOOP
A filling loop is supplied loose with the appliance for connecting the
mains water supply to the CH system so that the system can be filled on
installation or whenever water pressure has been removed for system
modifications, etc. The filling loop complies with the current water
supply (water fittings) regulations.
Methods of filling a sealed system are shown in Figure 8.
WATER TREATMENT, CLEANSING AND FLUSHING THE HEATING
SYSTEM
NOTE:
British Standard BS7593: 1992 stresses the importance of
cleansing and flushing of the system to ensure it continues to run
efficiently with the minimum of maintenance necessary. Halstead
Boilers fully support this professional approach and recommend that
the system is cleansed with an effective chemical cleanser and
protected long term with a suitable inhibitor. Such products are
available from Fernox and Sentinal.
CONTROLS.
As a minimum it is recommended that a room thermostat
be installed to control the appliance. Thermostatic radiator valves may
be fitted to the system, however they must not be fitted in the room
where the room thermostat is fitted. There must be at least one radiator
installed with lock shield valves that should not be closed. Further
guidance can be obtained from the Domestic Heating and Hot Water
Guide to the building regulations.
DOMESTIC HOT WATER SYSTEM
(CBX APPLIANCES ONLY)
3.8
a)
Check that the mains water pressure is sufficient (as stated in 2.2
“Performance Data”) to produce the required DHW flow rate, but
does not exceed the maximum DHW pressure (10 bar). If
necessary, a pressure-reducing valve must be fitted to the mains
supply before the DHW inlet connection.
b)
The final 600 mm (24 in) of the mains supply pipe to the boiler must
be copper.
c)
Avoid long DHW pipe runs and several hot water draw off points.
d)
Insulate the hot water pipes if accessible to minimise the heat
losses within the pipes to keep the water hot longer.
e)
A domestic hot water regulator is fitted within the appliance to
control the maximum water flow rate. This may be removed to
obtain higher flow rates. Higher flow rates will not damage the
appliance but may reduce the water temperature below an
acceptable level.
DOMESTIC HOT / COLD WATER SUPPLY TAPS AND MIXING TAPS.
All equipment designed for use at mains water pressure is suitable.
SHOWERS & BIDETS.
Any mains pressure shower or bidet complying with the Local Water
Undertaking byelaws is suitable.
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