Bosch Worcester 15SBi Installation And Servicing Instructions page 3

2.7 System
All dirt must be flushed from the system before connecting the
appliance. Refer to Fig. 5,6 and 7.
The system can be pre-piped and flushed before the appliance is
fitted.
The connections in the system must withstand a pressure of up
to 3 bar.
Radiator valves must conform to BS2767:10:1977.
2.8 Domestic Hot Water
Single feed direct cylinders are not suitable and must not be
used.
A HW cylinder must be of the indirect coil type and suitable for
working at a gauge pressure of, at least, 0.35bar above the relief
valve setting.
Where a storage system will not have a vent to atmosphere the
installation must comply with Building Regulations and Water
Company bye-laws. If connecting to an existing system the local
authority should be informed.
2.9 Safety
The appliance must not be operated with the inner casing cover
removed.
The gas and electricity supplies must be turned off before
servicing or working on the appliance.
Fig. 1. Water flow diagram.
Automatic air vent
Pump
Optional diverter valve
Combustion
By-pass
Cylinder Cold in
C.H.
flow
flow
(with optional
diverter valve
only)
3
IMPORTANT: Where back-flow prevention devices, including
water meters, are fitted the expansion of hot water into cold
water main can be prevented. This can result in a pressure
build-up that may cause damage to the boiler and household
devices such as showers, washing machines etc.
In these cases we recommend that a mini-expansion vessel
be fitted adjacent to the boiler in the cold water pipe.
2.10 Operation
Central Heating
A demand for heat will ignite the burner. The temperature is
controlled by the integral sensor. At the end of the demand the
burner will go out and the pump will continue to run for up to 3
minutes to dissipate the heat.
Domestic Hot Water:
The supply of domestic hot water depends upon the type of hot
water equipment installed and the control system. Refer to the
separate leaflet.
The use of unvented cylinders must be in accordance with the
manufacturers instructions relevant to British Standards
Chamber
Return Relief
valve
discharge
Gas to water heat
exchanger
Expansion vessel