Bosch Worcester 15SBi User Instructions & Customer Care Manual page 4

Fig. 1. System Diagram.
Automatic air
vent
Circulating
pump
Diverter valve
CH
(optional)
flow
4
Central Heating
trols (i.e. a programmer or room thermostat). The pump will energise
circulating primary water around the heating system and the burner
will light. The heat output from the appliance in this mode has been
factory set to mid-range or as reset by your installer. The appliance
Domestic
Domestic
hot water
cold sup-
out
ply
When a demand is made for heating by the system con-
Gas to water
heat exchanger
Boiler
Expansion
vessel
Pressure
relief valve
CH
Relief Valve
return
discharge
will operate as necessary
to maintain the tempera-
ture of the radiators at
the level set by the adjust-
ment of the Heating
Temperature Control
Knob. (See Fig. 2.)
If the system no
longer requires output to
maintain the desired
room temperature, the
burner will extinguish.
The pump will continue
to run for a short period
to dissipate the residual
heat from the appliance
and then switch off.
The appliance will
supply heat to the central
heating system as
required.