11
9
System guidance
The boiler is suitable for sealed systems only. The
maximum cold water mains pressure for the appliance is 10
bar. All fittings and pipework connected to the appliance
should be of the same standard. If there is a possibility of
the incoming mains pressure exceeding 10 bar, particularly
at night, then a suitable pressure limiting valve must be
fitted.
The boiler is designed to provide hot water on demand. If
there is a requirement for greater demands, for example if
the property has several bathrooms and cloakrooms, a
vented or unvented hot water storage system should be
used.
Showers
Any shower valves used with the appliance should be of a
thermostatic or pressure balanced type. Refer to the
shower manufacturer for performance guidance and
suitability.
Flushing and Water Treatment
The performance of the appliance could be impaired by
system debris or the effects of corrosion. The system must
be flushed thoroughly to remove metal filings, solder,
machining oils and other fluxes and greases before
connecting the boiler. If it is an existing system, an
appropriate flushing and descaling agent should be used.
Refer to BS 7593 (1992) for guidance. For more information
on the use of corrosion inhibitors, flushing and descaling
agents, advice can be sought from the manufacturers of
water treatment products such as:
Betz Dearborn Ltd
Foundry Lane
Widnes
Cheshire
WA8 8UD
Tel: 0151 424 5351
Fernox Manufacturing
Britannica Works
Clavering
Essex
CB11 4QZ
Tel: 01799 550811
System Controls
The boiler is electrically controlled and is suitable for most
modern electronic time and temperature controls. The
addition of such external controls can be beneficial to the
efficient operation of the system. The boiler connections for
external controls are 24V and so only controls of 24V or that
have voltage free contacts should be used.
By pass and Pump
The boiler is fitted with an automatic by pass. Although
adjustment is not necessary.
Expansion Vessel
The expansion vessel is pre-charged to 0.7 bar (10 lb/in
2
).
The vessel is suitable for systems up to 145 litres capacity.
For systems of greater capacity an additional expansion
vessel will be required. Refer to the chart below and BS
7074 pt 1 or BS 5449.
Filling Point
Provision must be made to be able to charge the system on
commissioning and to make up any subsequent pressure
loss.
The method of connection must utilise approved equipment
and must comply with the water regulations. A filling loop
can be so installed as to be hidden beneath the boiler.
20
40
60
80
100
120
Pf
140
160
180
200
220
240
0,7
0,8
0,9
1,0
1,1
1,2
1,3
1,4
1,5
1,6
1,7
1,8
1,9
2,0
80
°
C
70
°
C
60
°
C
50
°
C
40
°
C
260
Pression à froid pour le circuit chauffage (en bar)
Liters
Pressure
System capacity chart
Fig. 15
