12
9
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
Capacité maximale de l'installation (en litres)
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. 21
System Guidance
