Worcester GREENSTAR 24i junior User manual

Greenstar 24i junior / 28i junior
WALL HUNG GAS-FIRED CONDENSING COMBINATION BOILER
FOR SEALED CENTRAL HEATING SYSTEMS & DOMESTIC HOT WATER
USER INSTRUCTIONS &
CUSTOMER CARE GUIDE
THIS APPLIANCE IS FOR USE WITH
NATURAL GAS OR LPG (Cat II 2H3P TYPE C13 & C33)
24i junior NATURAL GAS: 47 311 86
24i junior LIQUID PETROLEUM GAS: 47 311 90
28i junior NATURAL GAS: 47 311 87
28i junior LIQUID PETROLEUM GAS: 47 311 91

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CONTACT INFORMATION
WORCESTER BOSCH:
TECHNICAL: 08705 266241
SERVICE: 08457 256206
SPARES: 01905 752571
LITERATURE: 01905 752556
TRAINING: 01905 752526
SALES: 01905 752640
WEBSITE: www.worcester-bosch.co.uk
WATER TREATMENT:
FERNOX 01799 550811
www.fernox.com
SENTINEL 0151 420 9595
www.betzdearborn.com/sentinel
FLUE TERMINAL GUARDS:
TOWER FLUE COMPONENTS
Vale Rise, Tonbridge TN9 1TB
USER INSTRUCTIONS & CUSTOMER
CARE GUIDE
PLEASE READ THESE INSTRUCTIONS
CAREFULLY BEFORE OPERATING YOUR
APPLIANCE
THESE INSTRUCTIONS ARE APPLICABLE TO
THE WORCESTER BOSCH APPLIANCE
MODEL(S) STATED ON THE FRONT COVER OF
THIS MANUAL ONLY AND MUST NOT BE USED
WITH ANY OTHER MAKE OR MODEL OF
APPLIANCE.
THE INSTRUCTIONS APPLY IN THE UK ONLY
AND SHOULD BE FOLLOWED EXCEPT FOR
ANY STATUTORY OBLIGATION.
IF YOU ARE IN ANY DOUBT CONTACT THE
WORCESTER BOSCH TECHNICAL HELPLINE.
DISTANCE LEARNING AND TRAINING
COURSES ARE AVAILABLE FROM
WORCESTER BOSCH.
THIS APPLIANCE MUST BE INSTALLED BY A
COMPETENT PERSON. FAILURE TO INSTALL
CORRECTLY COULD LEAD TO PROSECUTION.
PLEASE LEAVE THIS GUIDE, THE
INSTALLATION INSTRUCTIONS AND THE
COMPLETED BENCHMARK LOG BOOK WITH
THE USER OR AT THE GAS METER AFTER
INSTALLATION.
ABBREVIATIONS USED IN THIS BOOK:
NG - Natural Gas
LPG - Liquid Petroleum Gas
CH - Central Heating
SEDBUK - Seasonal Efficiency of Domestic
Boilers in the United Kingdom
USER INSTRUCTIONS &
CUSTOMER CARE GUIDE
WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)

CONTENTS
WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
1
CONTENTS
INTRODUCTION
EXCELLENCE COMES AS STANDARD 2
SAFETY PRECAUTIONS 3
GENERAL NOTES 4
USING YOUR APPLIANCE
CONTROLS 6
OPERATING THE APPLIANCE 7
Switching the appliance on/off 7
Setting the central heating temperature 7
Controlling central heating 7
Frost protection 7
Controlling domestic hot water 8
Fault condition 9
ENERGY SAVING
TIPS ON ENERGY SAVING 10
MAINTENANCE
MAINTAINING YOUR APPLIANCE 13
FAULT FINDING 14
FAULT OR BREAKDOWN 15
GUARANTEE
YOUR GUARANTEE 16
GUARANTEE REGISTRATION 17
INTRODUCTION
USING YOUR
APPLIANCE
MAINTENANCE ENERGY
SAVING
GUARANTEE

EXCELLENCE COMES AS STANDARD WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
2
EXCELLENCE COMES AS STANDARD
Thank you for purchasing a Greenstar 24i Junior
/ 28i Junior gas-fired condensing combination
boiler manufactured by Worcester Bosch. The
company prides itself on manufacturing boilers
to the strictest quality control standards
throughout every stage of production.
Worcester Bosch has led the field in innovative
appliance design and performance for more
than 40 years. This heritage means all products
are of exceptional quality and proven reliability.
The Greenstar range in particular is extremely
energy efficient, converting up to 97% of gas
consumed into heat, offering you economical
running costs and value for money. It sits in
SEDBUK Band A, and is therefore amongst the
top energy rated appliances available.
There is also the reassurance of our no-
nonsense 2 years parts and labour guarantee -
backed up by Worcester Total Cover, an
optional complete maintenance scheme to keep
your boiler operating at peak condition and
efficiency.
To find out more about Worcester Bosch log
onto www.worcester-bosch.co.uk .
INTRODUCTION

SAFETY PRECAUTIONS
WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
3
IF YOU SMELL GAS:
✗DON’T SMOKE OR STRIKE MATCHES
✗DON’T TURN ELECTRICAL SWITCHES ON OR OFF
✓DO PUT OUT NAKED FLAMES
✓DO OPEN DOORS AND WINDOWS
✓DO KEEP PEOPLE AWAY FROM THE AREA AFFECTED
✓DO TURN OFF THE CONTROL VALVE AT THE METER
✓DO CALL YOUR GAS COMPANY
BENCHMARK STANDARD
‘Benchmark’ is a code of practice for correctly
installing, commissioning and servicing of
domestic water heating appliances.
A Benchmark Checklist is provided by the
manufacturer for the installer to complete ALL
details together with their CORGI registration
number and sign to confirm that the boiler has
been installed and commissioned according to
the manufacturer’s instructions.
IMPORTANT: The completed Benchmark
Checklist will be required in the event of any
warranty work and may be required by the local
Building Control Inspector.
HEALTH & SAFETY
The appliance contains no asbestos and no
substances used in the construction process
that contravene the COSHH Regulations
(Control of Substances Hazardous to Health
Regulations 1988).
COMBUSTIBLE AND CORROSIVE MATERIALS
Do not store or use any combustible materials
(paper, thinners, paints etc.) inside or within the
vicinity of the appliance.
Chemically aggressive substances, such as
halogenated hydrocarbons containing chlorine
or fluorine compounds can corrode the
appliance and invalidate any warranty.
FITTING & MODIFICATIONS
Fitting the appliance, any controls to the
appliance and removal of the outer casing may
only be carried out by a competent engineer in
accordance with the Gas Safety (Installation
and Use) Regulations.
Flue systems must not be modified in any way
other than as described in the Installation
instructions and any misuse or unauthorised
modifications to the appliance, flue or
associated components and systems could
invalidate the warranty. The manufacturer
accepts no liability arising from any such
actions. This does not affect your statutory
rights.
SERVICING
The user is recommended to have the system
regularly serviced by a competent, qualified
engineer (such as British Gas or CORGI
registered personnel) using original spares, to
help maintain the economy, safety and reliability
of the appliance and to have the Service
Record completed in the Benchmark Checklist.
The appliance should be serviced annually after
installation unless the particular installation
conditions and usage demand more frequent
services.
IMPORTANT - ensure that the service engineer
completes the Service Record in the
Benchmark Checklist after each service.
INTRODUCTION
SAFETY PRECAUTIONS

GENERAL NOTES WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
4
To get the best from your appliance please read
these instructions carefully.
SEALED HEATING SYSTEMS
This appliance is fitted to a sealed heating
system which is pre-pressurised. Your installer
will advise you of the minimum and maximum
pressure which should be indicated on the
pressure gauge.
Check regularly that the pressure is maintained
and contact your installer or maintenance
engineer if a permanent significant drop in
pressure is indicated on the pressure gauge. If
the system loses pressure it should be re-
pressurised and the cause of the fall
investigated.
CENTRAL HEATING SYSTEMS
During the first few hours of operation of the
central heating system, check that all radiators
are being heated at an even rate. If the top of a
radiator is at a lower temperature than the
bottom then it should be vented by releasing air
through the venting screw at the top of the
radiator. Ask your installer to show you how this
is done.
This boiler is fitted to a sealed system; repeated
venting will reduce the quantity of water in the
system and this must be replenished for safe
and satisfactory operation of the appliance.
Should water leaks be found in the system or if
excessive venting is required, then a service
engineer must be contacted to inspect the
installation and rectify any fault.
Only additives that are compatible with
aluminium may be used in the system. Any
incompatible additive used will invalidate the
guarantee.
CONDENSATE DRAIN
This is a condensing appliance and the terminal
will, at times give out a plume of water vapour.
This is quite normal.
The appliance also produces quantities of
condensate which is discharged regularly by a
siphon within the boiler via a pipe to drain. This
pipe must not be blocked or altered in any way.
CLEARANCES - VENTILATED COMPARTMENT
Your installer will have provided adequate
space around the appliance for safety and
servicing access. Do not restrict this space with
the addition of cupboards, shelves etc. next to
the appliance.
GENERAL NOTES
ROOM THERMOSTAT
A room temperature controller and programmer
should be fitted to control the central heating.
Refer to the instructions supplied with the
thermostat for information on siting and setting.
THERMOSTATIC RADIATOR VALVES
It is recommended that this type of valve is
fitted to all but one of the radiators (or at least
those in the sleeping accommodation). The
remaining radiator, which must be where the
room thermostat is located, should be un-
controlled and must be left open. The
thermostatic radiator valves should conform to
the requirements of BS2767:10.
INTRODUCTION
+ 30mm
above elbow
5mm
5mm
600mm
200mm
*600mm
(**25mm)
*600mm service clearance required to a fixed surface
(**25mm from removable door or panel)

SAFETY PRECAUTIONS
WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
5
BOILER CLEARANCES - UNVENTILATED
COMPARTMENT
The diagram opposite shows the minimum
space required to install and service the boiler
inside an unventilated compartment.
** Space required for unventilated areas with a
removable door or panel.
*** 600mm clearance required to a fixed
surface for servicing.
* This space can be reduced to 50mm for one
side only provided that the total side clearances
add up to 400mm or more.
VENTILATION
This is a room sealed appliance and does not
require any air for combustion from inside the
property. If the appliance is fitted into a
cupboard or a compartment is built around the
appliance after installation, then the
compartment must be separated from the boiler
space by a perforated non-combustible partition
as described in BS 6798.
Notwithstanding the requirements of BS 6798
and BS 5440 there is no need for ventilation
openings to be provided in the compartment
because of the low heat loss from the appliance
casing, if the clearances shown are maintained.
Do not operate the appliance if the flue terminal
fitted on the outside wall or roof is obstructed
or damaged.
PUMP ANTI-SEIZURE
If there has been no heating demand for 24
hours the boiler will run the system pump for a
few seconds to reduce the possibility of pump
seizure during long periods of inactivity, which
is usually more frequent during the summer
months.
GENERAL NOTES
INTRODUCTION
+ 30mm
above elbow
200mm*
200mm*
100mm**
600mm***
200mm
**
***

CONTROLS WORCESTER BOSCH GREENSTAR 24i/28i Junior
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6
CONTROLS
1. MASTER SWITCH FOR ON/OFF
2. CENTRAL HEATING
TEMPERATURE CONTROL
3. MAINS ON/OFF INDICATOR + FAULT
DIAGNOSTIC LIGHT
4. BURNER ON INDICATOR LIGHT (GREEN)
5. ECO BUTTON (DOMESTIC HOT WATER
PRE-HEAT ON/OFF)
6. FAULT RESET BUTTON
7. SYSTEM PRESSURE GAUGE
8. POSITION FOR OPTIONAL PROGRAMMER
USING YOUR
APPLIANCE
1
2
46
87
5
3

OPERATING THE APPLIANCE
WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
7
SWITCHING THE APPLIANCE ON/OFF
Switching on
Switch on the appliance by pressing the master
switch.
The indicator light shows blue
Switching off
Switch off the appliance by pressing the master
switch.
The blue indicator light goes out.
SETTING THE CENTRAL HEATING TEMPERATURE
Turn the central heating temperature control to
the desired level, between 40°C and 82°C
When the burner is lit, the green indicator light
underneath the on/off switch is illuminated.
CONTROLLING CENTRAL HEATING
Set the timer to the correct time.
Set room thermostat to the desired room
temperature.
Set the thermostatic radiator valves to the
desired settings.
FROST PROTECTION
Leave master switch on.
Turn the central heating temperature control
to.
If the temperature falls to 5°C within the boiler it
will fire to avoid the possibility of freezing.
Add a suitable anti-freeze fluid to the water in
the central heating system.
If remote pipework is likely to be subjected to
freezing conditions, ensure the installer has
fitted a frost thermostat in the area to protect
the pipework.
OPERATING THE APPLIANCE
USING YOUR
APPLIANCE
4
4
4
4
4
4
4
4
4
4

HOT WATER TEMPERATURE
The hot water temperature is fixed at 55°C and
can not be adjusted.
DOMESTIC HOT WATER PRE-HEAT
Pre-heat reduces the time taken to produce hot
water at the tap and is controlled by the ECO
button.
Press the ECO button to select either:
When the ECO button is not illuminated the
boiler will be in pre-heat mode (which will
reduce the time taken to produce hot water at
the tap).
OR
When the ECO button is illuminated the boiler
will be in ECO mode with no pre-heat available.
OPERATING THE APPLIANCE
4
OPERATING THE APPLIANCE WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
8
USING YOUR
APPLIANCE

FAULT CONDITION
In the unlikely event of a fault occurring while
the appliance is in operation:
The reset button will flash once per second and
the mains indicator (blue light) will flash at different
speeds dependent on fault.
To reset boiler press the reset button.
The reset button will no longer be illuminated
and the mains indicator will stop flashing.
The boiler will function normally, dependent on
programmer and room thermostat settings.
If the fault remains and cannot be cleared by
pressing the reset button, or if fault persists
contact Worcester Bosch for assistance, giving
a description of the fault and, if possible, the
fault flashing sequence from the mains
indicator.
OPERATING THE APPLIANCE
4
OPERATING THE APPLIANCE
WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
9
USING YOUR
APPLIANCE

Heating economically
The boiler is designed to provide a high level of
comfort while keeping gas consumption and the
resulting environmental effect as low as
possible. The gas supply to the burner is
controlled according to the level of demand for
heat. The boiler continues to operate with a low
flame if the demand for heat reduces. The
technical term for this process is modulating
control. Modulating control reduces
temperature fluctuations and provides even
distribution of heat throughout the home. This
means that the boiler may stay on for relatively
long periods but will use less gas than an
appliance that continually switches on and off.
Central heating systems with room
thermostats/thermostatic radiator valves
The central heating control on the boiler should
be set to the maximum rated temperature of the
central heating system.
The temperature of each room can be set
individually (except primary room with the room
thermostat) using the thermostatic radiator
valves.
TIPS ON ENERGY SAVING
TIPS ON ENERGY SAVING WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
10
ENERGY
SAVING

Roof insulation
Around 30% of the heat loss from a property is
through the roof. Replace any old insulation
with new insulation, preferably of around
200mm thickness or more.
Window frames
Single glazed windows, particularly those with
steel frames, can lose a great deal of heat.
Consideration should be given to replacement
with PVCu or wooden framed double glazed
units.
Curtains
Lined curtains, or heavier full length curtains
can provide excellent insulation. However,
always ensure that the curtains do not drape
over radiators.
Draughts
Try to ensure that draughts around doors,
windows, letterboxes and keyholes etc. are
reduced by using a suitable draught excluder.
Warning - Do not block or seal any air vents
that are installed to ensure the central heating
boiler operates safely.
Room thermostats
Reducing the setting of the room thermostat by
1°C can reduce fuel consumption by up to 10%.
New control systems
Upgrade your heating control system if
necessary with the latest equipment available.
The minimum level of control is a programmer,
interlocking room thermostat and thermostatic
radiator valves.
TIPS ON ENERGY SAVING
TIPS ON ENERGY SAVING
WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
11
ENERGY
SAVING

Radiators
More often than not radiators will be sited
underneath a window, so the warm air from the
radiator heats the colder incoming air from the
window. The performance of the radiator will be
affected if the curtains are allowed to drape
over the radiator or shelves are fitted above it.
The positioning of furniture and tables in front
of the radiator should also be avoided.
It is advisable to manually adjust all radiator
thermostatic valves every 2-3 months to prevent
them sticking. It is also important that the
plastic tops of all valves are always in position
and not cracked or damaged to prevent
accidents. Care should be taken when vacuum
cleaning carpets to avoid damage to valves and
pipework.
The heating system and the outputs of the
radiators have been carefully selected by your
installer. The temperature obtainable in any
given room is dependent on all radiators being
operated at the same time. If you decide to turn
off radiators in unused rooms, spare bedrooms
etc., you may experience slightly lower room
temperatures in rooms adjacent to unheated
rooms.
TIPS ON ENERGY SAVING
TIPS ON ENERGY SAVING WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
12
ENERGY
SAVING

Your new Greenstar 24i Junior / 28i Junior 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 servicing and
maintenance checks from a competent person
beyond the initial 2 year guarantee period.
If you would like to know more about a
Worcester Bosch service contract, please tick
the appropriate box on your warranty
registration card.
If your Greenstar 24i Junior / 28i Junior should
fail to operate correctly or requires servicing
please contact the Worcester Bosch Service
Department (see inside front cover for details).
Details of the boiler including the Gas Council
number can be found under the controls cover
flap on the boiler.
MAINTAINING YOUR APPLIANCE
MAINTAINING YOUR APPLIANCE
WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
13
MAINTENANCE

FAULT FINDING
Problem Cause Remedy
Switch off appliance at
master switch, wait a few
seconds then switch on
again
Check setting
Reduce flow rate at tap
Desired room
temperature is not
reached
Thermostatic radiator
valve(s) set too low
Temperature control for
CH flow on boiler set too
low
Air trapped in heating
system
Desired room
temperature exceeded by
large amount
Heating stays on for too
long
No on/off indicator
Hot water temperature
too low
Radiators are too hot
Clock is incorrectly set
Momentary power failure
Programmer setting
Water flow at tap too high
Increase thermostatic
radiator valve setting(s)
Increase CH flow
temperature control
setting
Bleed radiators and
recharge heating system
Turn down thermostatic
radiator valves / room
thermostat
Reduce central heating
temperature on boiler
Check setting
FAULT FINDING WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
14
MAINTENANCE
This table gives information on basic operating
system problems.
In the unlikely event of a boiler fault please read
the following page thoroughly before contacting
Worcester Bosch.

This appliance is supported in the UK by
Worcester, Bosch Group.
Specialist factory trained Service Engineers are
available to attend a breakdown occurring on
this appliance.
No charge will be made for parts and/or
labour providing:
An appliance fault is found and the appliance
has been installed within the past 24 months.
Reasonable evidence of this must be supplied
on request. i.e. the Benchmark Checklist.
A call-out charge will be made where:
The appliance has been installed for over 24
months
OR
Our Field Service Engineer finds no fault with
the appliance (see Note).
OR
The cause of breakdown is misuse or with
other parts of your plumbing/heating system,
or with equipment not supplied by Worcester
Bosch.
Note. NO APPLIANCE FAULT IS FOUND ON
OVER 30% OF ALL SERVICE CALL OUTS.
Please read this guide carefully to gain a good
understanding of the operation of your
appliance. In the case of a suspected fault,
refer to the fault finding section of this guide.
If in doubt contact our Technical Helpline
In the event of an appliance fault or breakdown
please contact our Service Department. Your
service administrator will arrange for an
engineer to call with the minimum of delay;
under normal circumstances this will be from 1
- 3 working days (excluding weekends) for
priority breakdown situations (no hot water
and/or heating).
Invoices for attendance and repair work carried
out on this appliance by any third party will not
be accepted.
FAULT OR BREAKDOWN
4
4
4
4
FAULT OR BREAKDOWN
WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
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MAINTENANCE

This appliance is guaranteed against faulty
material or workmanship for a period of 2 years
from the date of installation subject to the
following terms and conditions.
Your Guarantee Registration Card must be
returned within 30 days for the second year
of you guarantee to become valid.
During the period of this guarantee any
components of the unit which are proven to
be faulty or defective in manufacture will be
exchanged or repaired free of charge by
BBT Thermotechnology UK Ltd.
The householder may be asked to prove the
date of installation, that the appliance was
correctly commissioned and, where
appropriate, the first year’s service inspection
has been carried out to the satisfaction of
BBT Thermotechnology UK Ltd. when
requested. These should be part of the
Benchmark Checklist.
Any product or part returned for servicing
under the guarantee must be accompanied
by a claim stating the model, serial number &
date of installation.
BBT Thermotechnology UK Ltd. will not
accept responsibility for damage caused by
faulty installation, neglect, misuse or
accidental damage or the non-observance of
the instructions contained in the Installation
and Servicing Manual and User Instructions.
The appliance has been used only for the
normal domestic purposes for which it was
designed.
This guarantee applies only to equipment
purchased and used in the United Kingdom.
This guarantee does not affect your statutory
rights.
YOUR GUARANTEE
4
4
4
4
4
4
YOUR GUARANTEE WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
16
GUARANTEE

You should complete and return the postpaid
Guarantee Registration Card within 14 days of
purchase.
Returning the card will register you as the
owner of your new Greenstar 24i Junior / 28i
Junior appliance and will assist us in
maintaining an effective and efficient customer
service by establishing a reference and
permanent record for your boiler.
This does not affect your statutory rights.
For your own record:
Check that the Benchmark Checklist has been
completed by your installer or service engineer.
GUARANTEE REGISTRATION
Model
Serial No.
(See guarantee card)
Type / size
Date of installation
GUARANTEE REGISTRATION
WORCESTER BOSCH GREENSTAR 24i/28i Junior
8 716 107 338b (11.05)
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GUARANTEE