Bosch Worcester 15SBi User manual

15/24SBi SYSTEM BOILER
USER INSTRUCTIONS &
CUSTOMER CARE GUIDE
IMPORTANT: THIS APPLIANCE IS FOR USE WITH NATURAL GAS OR LPG.
THESE INSTRUCTIONS APPLY IN THE UK ONLY.
THESE INSTRUCTIONS ARE TO BE LEFT WITH THE USER OR AT THE GAS METER
G. C. NUMBERS
APPLIANCE NATURAL GAS L. P. G.
15SBi 41 311 43 41 311 45
24SBi 41 311 44 41 311 46
SBi
Worcester supports the
Benchmark code of practice
Vote for your
‘Installer of the year’ at
www.worcester-bosch.co.uk

EXCELLENCE COMES
AS STANDARD
Thank you for purchasing a Worcester SBi gas-fired system
boiler.
The SBi Series appliances are made by Worcester and the
strictest quality control standards are demanded throughout
every stage of production.
Indeed, Worcester, part of the Bosch Group have led the
field in innovative appli-
ance design and perform-
ance for more than 40
years.
The result is
that your new Worcester
system boiler appliance
offers you the very best of
everything - quality, effi-
ciency, economical run-
ning costs, proven reliabil-
ity and value for money.
What’s more, you also have the assurance of our no-
nonsense 1 year parts and labour guarantee.
Page No.
Operating Instructions
.................................... 3-11
Fault and Breakdowns 12
Maintenance and
Extended Warranty
Information ............ 13-14
Guarantee Details .. 15-16
CONTENTS
2

GENERAL
INFORMATION
GAS SAFETY (INSTALLATION AND USE)
REGULATIONS 1998
It is the law, in GB, that all gas appliances must be installed by a
competent person in accordance with the above regulations. Failure
to install appliances correctly could lead to prosecution. It is in your
interest and that of safety to ensure compliance with the law. The
manufacturer’s notes must not be taken, in any way, as over-riding
statutory obligations.
In GB, a competent person is someone registered with CORGI.
All CORGI registered installers carry a CORGI ID card and have a regis-
tration number. Both should be recorded in the BENCHMARK check-
list. You can check that your installer is CORGI registered by calling
CORGI on 01256 372300.
WARNING: This appliance must be earthed and protected by a
3 amp fuse.
ELECTRICITY SUPPLY: 230V ~ 50Hz
IMPORTANT: To get the best from your Worcester system boiler
please read these instructions carefully.
In the event of a fault the appliance should not be used until the
fault has been corrected by a competent person.
BENCHMARK
The Benchmark initiative is a code of practice to encourage
the correct installation, commissioning and servicing of domestic cen-
tral heating boilers and system equipment.
A checklist can be found in the back of every installation
manual. This is a vital document that needs to be completed by the
installer at the time of installation. It confirms that the boiler has
been installed and commissioned according to the manufacturers
instructions.
In Eire the declaration found in IS 813 must be complet-
ed. Without completion of the checklist and/or declaration, manufac-
turers may refuse to respond to a call-out request. It is important that
the checklist and/or declaration are fully completed by your installer.
GENERAL DESCRIPTION
(See Fig.1.)
The WORCESTER system boilers are sealed system central heat-
ing aplliances. They consist of a gas fired boiler having a varying out-
put of between 6 - 15kW (15SBi) and 15 - 24kW (24SBi), a circulating
pump and all necessary controls to provide central heating.
They can be connected to a domestic hot water supply system
through an optional, internally fitted diverter valve or to an external
S or Y plan system.
Central Heating
3

4
Central Heating
When a demand is made for heating by the system con-
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
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.
Fig. 1. System Diagram.
Automatic air
vent
Gas to water
heat exchanger
Circulating
pump
Diverter valve
(optional) CH
flow
Domestic
hot water
out
Domestic
cold sup-
ply
CH
return
Relief Valve
discharge
Pressure
relief valve
Boiler
Expansion
vessel

5
CENTRAL HEATING SYSTEM
During the first few hours of operation of the central heating
system, check that all radiators are being heated at an even rate.
Should the upper area of a radiator be at a lower temperature than
the base of the radiator, it should be vented by releasing air through
the venting screw at the top of each radiator. Make sure your installer
shows you how to carry out the operation. Repeated venting will
reduce the quantity of water in the system and this must be replen-
ished for safe and satisfactory operation of the appliance. Should
water leaks be found in the system or excessive venting be required
from any radiator, a service engineer should be contacted and the sys-
tem corrected.
SEALED HEATING SYSTEM
The appliance must be fitted to a sealed heating
system which is pre-pressurised. In this case your
installer will advise you on the minimum and maximum
pressure that should be indicated on the pressure gauge.
See Fig. 3. Check regularly that this pressure is main-
tained and contact your installer or maintenance engi-
neer if there is a permanent significant drop in pressure
indicated on the gauge. If the system loses pressure it
should be re-pressurised as instructed by the installer
(N.B. Maximum operating pressure 2.5 bar).
Pressurising The System (See Fig. 2).
(If in doubt leave this procedure to your installer).
Remove the bottom panel to gain access to the fill-
ing loop assembly.
Insert the bayonet end of the filling key into the
corresponding cut outs in the filling loop housing and
twist to lock the key in place.
Turn the grey knob anti-clockwise to allow water
ingress and fill until the required pressure is reached.
Turn the grey knob clockwise to stop filling and
remove the filling key by lining up the bayonet end of
the key with the cut outs in the filling loop housing and
withdrawing the key.
N.B. The key must always be removed from the
filling loop housing after the system has been filled to
prevent accidental filling and to comply with Byelaw
14 of the Water Byelaws Scheme.
Store the key in a safe place for future use and
refit the bottom panel
GENERAL NOTES
Grey
Knob
Filling Key
Fig. 2.

6
CLEARANCES
Your installer will
have provided adequate
space around the appliance
for safety and servicing. Do
not restrict this space by
the addition of cupboards,
shelves etc. close to the
appliance.
Minimum clearances in millimetres.
ROOM THERMOSTAT
A room thermostat may be fitted for control of the central heat-
ing temperature. It will be located in one room of the home. The
method of setting a room thermostat varies with the type and manu-
facture. Refer to the instructions supplied with the room thermostat.
THERMOSTATIC RADIATOR VALVES
If thermostatic radiator valves are fitted to the system then they
must conform to the requirements of BS2767. The radiator located in
the room where the room thermostat is sited must be controlled by a
thermostatic radiator valve.
VENTILATION OF ROOM SEALED FANNED
FLUE (RSF) APPLIANCES
These are room sealed appliances and any ventilation openings
in a wall or door must not be obstructed. Do not allow the flue termi-
nal fitted on the outside wall to become obstructed or damaged.
NOTE: Do not place anything on top of the appliance. If the
appliance is fitted in a compartment do not use the compartment for
storage purposes unless it conforms to the requirements of
BS 6798:1987: Section 6. It is essential that the airing space is separat-
ed from the boiler space by a perforated non-combustible partition as
described in BS 6798:1987.
CIRCULATING PUMP
This may be fitted with a speed adjuster. If so it will be factory
set at maximum and should be adjusted by the installer to suit the
heating load.
15SBi 24SBi
Left-hand side 10 10
Right-hand side 10 10
In Front 600 600
Above 180 180
Below 200 200

7
FROST PRECAUTIONS
If the appliance is not to be used for a long period of time and
there is a likelihood of freezing, then the appliance should be
drained. The Worcester Technical Helpline will advise you on suit-
able frost precautions.
SERVICE
Annual servicing is important in order to ensure continuing high
efficiency and long life for your appliance. In the event of any diffi-
culty in making suitable servicing arrangements, Worcester personnel
or other competent persons will discuss regular servicing arrange-
ments and offer a comprehensive maintenance contract.
WARNING
If a gas leak exists, or is suspected, turn off the gas supply to the
appliance at the service cock and consult your local service engineer.
Do not touch any electrical switches to turn them either on or off.
Open all windows and doors. Do not smoke. Extinguish all naked
lights.
CLEANING
Do not use abrasive cleaners on the outer casing. Use a damp
cloth and a little detergent.

8
OPERATION OF CON-
TROLS
(See also label on inside of appliance front panel).
The appliance is fitted with the following controls:
CENTRAL HEATING TEMPERATURE
CONTROL
The position of this knob will determine the temperature of the
water delivered to the radiators between the ‘I’ and ‘MAX’ position.
When the knob is turned anti-clockwise past the ‘I’ position to the
‘OFF’ (Summer Position) the appliance is off.
FACIA MOUNTED PROGRAMMER (if fitted)
Your installer may have mounted a mechanical programmer into
the facia of your appliance. Operating instructions are supplied with
the programmer.
RESET BUTTON
Press and release this button if the appliance fails to operate - if
the appliance still fails to operate then contact Worcester Bosch or
your installer.

9
Fig. 3. Controls.
Reset
button
Mains electricity
indicator
CH temperature
control knob
System pressure
gauge

10
INDICATOR LIGHTS
Green light:
MAINS : ‘ON’
TO LIGHT THE APPLIANCE
Check that the water valves to the central heating circuit are
open.
Check that the grey needle on the pressure gauge is not below
the required pressure.
Switch on the mains electricity. Set the room thermostat, if fit-
ted, to maximum. Turn the central heating temperature control knob
to ‘MAX’. The burner will light.. Set the central heating and hot water
temperature control knobs and the room thermostat/cylinder thermo-
stat, if fitted, to the desired temperature.
TO STOP THE APPLIANCE
For Short Periods
Turn the central heating temperature control knob fully anti-
clockwise to the ‘O’ position.
For Long Periods
Turn the CH temperature control
knob switch to the ‘O’ position. Switch
off the mains electricity.
A facia mounted mechanical pro-
grammer will require resetting if mains
supply has been disconnected.
ELECTRICITY SUPPLY
FAILURE
If
the electricity supply fails the appliance
will not operate. Once the supply is
restored the appliance will return to
normal operation. If a programmer is
fitted, check that the settings have
been maintained.
Fig. 4. 15/24SBi with front panel removed.
Circulating
pump
Clip
Locating peg
Expansion
vessel
Gas valve
TO LIGHT AND STOP THE
APPLIANCE