Worcester, Bosch Group, Cotswold Way, Warndon, Worcester WR4 9SW.
Telephone: 01905 754624 Fax: 01905 753130.
Technical Helpline 08705 266241.
Worcester, Bosch Group is a trading name of BBT Thermotechnology UK Limited
6 720 610 414b 10/05
134
Hot Water Mode:
The appliance operates to supply only domestic hot water when
the heating temperature mode is fully anti-clockwise, at the –position
or the timer is programmed to OFF mode.
The flow is limited within the appliance to give a hot water
delivery rate to a maximum of 9.0 (±15%) litres/minute-25Si or 10.0
(±15%) litres/minute-28Si.
Hot Water and
Central Heating
mode:
When a demand is made for
heating by the system controls
(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 maximum.
The appliance will operate as
necessary to maintain the
temperature of the radiators at
the level set by the adjustment
of the Heating Temperature
Control Knob. (See Fig. 2.)
If the system no longer
requires heat 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. A demand
for hot water at a tap or
shower will override the
central heating function for
the period of the domestic hot
water demand.
GUARANTEE
REGISTRATION
You should complete and return the postpaid Guarantee
Registration Card within 30 days of purchase.
The card will register you as the owner of your new
Worcester Si II appliance and, while this will not affect your
statutory rights in any way, it will assist us to maintain an
effective and efficient customer service by establishing a
reference and permanent record for your boiler.
IMPORTANT: SERIAL NUMBER. Copy the number off the
Guarantee Card.
FOR YOUR OWN RECORD
MODEL
SERIAL NUMBER
TYPE/SIZE DATE OF INSTALLATION
MAINTAINING YOUR
APPLIANCE
Your new Worcester Si gas-fired appliance represents a long-
term investment in a reliable, high quality product.
In order to realise its maximum working life, and to ensure
it continues to operate at peak efficiency and performance, it is
essential that your boiler receives regular, competent servicing
and annual maintenance checks beyond the initial 24 month
guarantee period*.
Regular service contracts can be arranged with your installer
– however if you have difficulty making a satisfactory
arrangement simply contact Worcester on
08457 256206 for help.
If you would like to know more about Worcester’s extended
warranty options please tick the appropriate box on your
warranty registration card.
*subject to terms and conditions on page 15.
Fig. 1. System Diagram. Automatic air
vent
Primary heat
exchanger
Circulating
pump
Fixed
by-pass
Relief valve
CH
flow
Domestic
hot water
flow
Domestic
cold
supply
CH
return
Relief valve
discharge
Domestic
water flow
turbine
Expansion
vessel
24-28Si II SERIES
USER INSTRUCTIONS &
CUSTOMER CARE GUIDE
G.C. NUMBERS
APPLIANCE NATURAL GAS L.P.G.
24Si II 47 311 65 47 311 66
28Si II 47 311 67 47 311 68
www.worcester-bosch.co.uk
Worcester supports the
Benchmark code of practice
CORGI CONTACT
All CORGI Registered installers carry a CORGI ID card and
have a registration number. Both should be recorded in your
central heating log book. You can check your installer is
CORGI Registered by calling CORGI on 01256 372300
Vote for your
‘Installer of the year’ at
www.worcester-bosch.co.uk
