Worcester GREENSTAR 24i junior User manual

24i /28i junior
USER INSTRUCTIONS &
CUSTOMER CARE GUIDE
G.C. NUMBERS
APPLIANCE NATURAL GAS L.P.G.
24i junior 47 311 69 47 311 71
28i junior 47 311 70 47 311 72

EXCELLENCE COMES
AS STANDARD
Page No.
Operating Instructions
.................................... 3-11
Fault and Breakdowns 12
Maintenance and
Extended Warranty
Information ............ 13-14
Guarantee Details ... 15-16
CONTENTS
2
Thank you for purchasing a Worcester ijunior Series gas-
fired combination appliance.
Worcester ijunior Series appliances are made by Worcester
Heat Systems and the strictest quality control standards are
demanded throughout every stage of production.
Indeed, Worcester Heat Systems have led the field in
innovative appliance
design and performance
for more than 30 years.
The result is that your
new Worcester ijunior
appliance offers you the
very best of everything -
quality, efficiency,
economical running costs,
proven reliability and
value for money.
What’s more, you also
have the assurance of our
no-nonsense 1 year parts
and labour guarantee.
And it’s backed up by Worcester Care Call - a complete
maintenance scheme to keep your boiler operating at peak
condition and efficiency.
No wonder that more and more people are agreeing that
when it is gas, it has to be Worcester ijunior Series.

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
manufacturers 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
registration number. Both should be recorded in your central heating
log book. You can check that your installer is CORGI registered by
calling CORGI on 01256 372300.
In Eire the installation must be in accordance with IS 813.
WARNING: This appliance must be earthed and protected by a 3
amp fuse to BS 1362.
ELECTRICITY SUPPLY: 230V ~ 50Hz
IMPORTANT: To get the best from your Worcester ijunior
appliance please read these instructions carefully.
NOTE: 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 central
heating boilers and system equipment.
A 'log book' is dispatched with every appliance, 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 completed.
Without the completion of the log book and/or the declaration,
manufacturers may refuse to respond to a call-out request. It is
important that your installer has given you the fully completed log
book and/or declaration.
GENERAL DESCRIPTION
The WORCESTER ijunior models are combined domestic hot
water and central heating appliances. They consist of a gas fired boiler
having a varying output of between 7.5kW and 23.5kW (24i junior) or
8.0 and 27.5kW (28i junior), and all the necessary controls to provide
mains fed domestic hot water and central heating.
The appliances can operate in one of two modes. Hot water only
or hot water and central heating.
3

4
A flow restrictor is fitted within the appliance which limits the
hot water delivery rate to a maximum of 8.0 (±15%) litres/minute
(1.8 gallons/minute) 24ijunior or 10 (±15%) litres/minute (2.2
gallons/minute) 28ijunior.
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 appliance will operate as necessary to maintain the
temperature of the radiators at the level set by the adjustment of the
Heating Temperature Control.
If the system no longer requires output to maintain the desired
room temperature, the burner will extinguish. The pump and fan 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.
Hot Water Only mode:
The appliance operates to supply only domestic hot water when
the heating temperature mode is fully anti-clockwise, at the position.

5
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.
SEALED HEATING SYSTEM
The appliance must be fitted to a sealed heating system which is
pre-pressurised. Your installer will advise you on the minimum and
maximum pressure that should be indicated on the pressure gauge.
See Fig. 1. Check regularly that this pressure is maintained and
contact your installer or maintenance engineer 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.
NOTE: The set pressure will normally be 1 to 1.5 bar. The
maximum operating pressure is 2.5 bar.
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
replenished 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 system corrected.
GENERAL NOTES

6
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.
NOTE: If the appliance is to be enclosed after the
installation then the instructions given in Section 4, Siting
the Appliance, of the Installation Book MUST be followed.
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. It is essential that the airing space is
separated from the boiler space by a perforated non-combustible
partition as described in BS 6798.
ROOM THERMOSTAT
A room thermostat must be fitted for control of the central
heating temperature. It will be located in one room of the home. The
method of setting a room thermostat varies with the type and
manufacture. 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. It is advisable to leave
one valve permanently set at maximum to prevent the boiler short
cycling.
SHOWERS, BIDETS, TAPS AND MIXING
VALVES
Standard hot and cold taps and mixing valves used with the
appliance must be suitable for operating at the available mains
pressure.
Thermostatically controlled shower valves will guard against the
flow of water at too high a temperature.
Hot and cold mains fed water can be supplied direct to an
overrim flushing bidet subject to local water company requirements.
With all mains fed systems the flow of water from the individual
taps will vary with the number of outlets operated simultaneously
and the cold water mains supply pressure to the property. Flow
balancing using ‘Ball-o-Fix’ type valves is recommended to avoid an
excessive reduction in flow to individual outlets.
For further information contact Worcester Heat Systems
Technical Helpline.
HOT AND COLD FLOW
The flow of water demanded from both hot and cold service
outlets is dependent upon mains supply and it may not be possible in
some installations to operate all outlets simultaneously.
WATER MAINS FAILURE
It is important to note that in the event of a mains water supply
failure, no tap water will be available until the mains supply is
restored. The appliance can still be used for heating as it is connected
to a sealed system.
Service
Left-hand side 10 25
Right-hand side 10 25
In Front 600 *25
Above flue elbow 30 30
Below 200 200
CLEARANCES
Unventilated
compartment
Minimum clearances in millimetres.
*Front clearance is to a removable
panel or door.

7
VENTILATION OF ROOM SEALED FANNED
FLUE APPLIANCES
These are room sealed appliances and do not require any
ventilation openings. Do not allow the flue terminal fitted on the
outside wall to become obstructed or damaged.
USE IN HARD WATER AREAS
Normally there is no need for scale protection. However, in areas
of exceptionally hard water supply it is recommended that an In-Line
scale inhibitor be fitted.
Installation should be strictly in accordance with the
requirements of the local Water Company. An isolating valve to
facilitate servicing should be incorporated.
The water hardness may be determined using the standard test
paper or by reference to the local Water Company.
Further information may be obtained from Worcester Heat
Systems Technical Helpline.
CIRCULATING PUMP
This may be fitted with a speed adjuster. If so it will be factory
set at maximum and should not be changed.
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 Heat Systems Technical Helpline will advise you on
suitable frost precautions. For short periods the built-in frost
protection of the appliance will be adequate.
SERVICE
Annual servicing is important in order to ensure continuing high
efficiency and long life for your appliance. In the event of any
difficulty in making suitable servicing arrangements, Worcester Heat
Systems Limited or other competent persons will discuss regular
servicing arrangements and offer a comprehensive maintenance
contract.
CLEANING
Do not use abrasive cleaners on the outer casing. Use a damp
cloth and a little detergent.
Under no circumstances should any seal on the boiler be broken.

8
▲
▲
CENTRAL HEATING TEMPERATURE
CONTROL
The position of this knob will determine the temperature of the
water delivered to the radiators between fully clockwise and anti-
clockwise to the mark. When the knob is turned anti-clockwise
past the position towards the ‘’(Summer Position), then the
appliance will operate in the HOT WATER mode only and no heat will
be delivered to the radiators.
HOT WATER TEMPERATURE CONTROL
There is no separate temperature control.
By slightly reducing the flow of domestic water from the tap, the
delivery temperature of the water will be further increased. This is of
particular advantage in the winter, for example to increase bath water
temperature and to remove heavy grease deposits on plates, etc. Also
this will provide an added advantage of reducing the delay before hot
water is obtained.
FACIA MOUNTED PROGRAMMER (if fitted)
Your installer may have mounted either a mechanical or an
electronic programmer into the facia of your appliance. Operating
instructions are supplied with the programmer.
RESET BUTTON
Press this button in for five seconds if the indicator light is
flashing slowly.
If indicator lamp is flashing fast turn power OFF and ON at the
switched socket supply to reset.
SYSTEM PRESSURE GAUGE
The black needle will show the actual pressure in the system.
When operating the pressure indicated must not be greater than
2.5bar. If it is then contact your installer.
OPERATION OF
CONTROLS

9
Fig. 1. Controls.
Fault indicator and
reset button
Flame detection
indicator
CH temperature
control knob
System pressure
gauge
!
Space for optional
plug in programmer
INDICATOR LIGHTS
Flame detection indicator:
OFF:Burner off
ON:Burner on
Fault indicator:
FLASHING SLOW:Ignition lockout or
(once per second) boiler overheat
FLASHING FAST: Appliance fault
(five times a second)

10
TO LIGHT AND STOP THE
APPLIANCE
CH Control in
fully clockwise position
CH Control in
fully anti-clockwise position
TO LIGHT THE APPLIANCE
Check that the water valves to the central heating circuit are open.
Check that the black needle on the pressure gauge is not below
the required system pressure.
Switch on the mains electricity. Set the room thermostat to
maximum. Turn the central heating temperature control knob fully
clockwise.
The burner will light and the red flame detection indicator will light.
Set the central heating temperature control knob and the room
thermostat, if fitted, to the desired temperature.
TO STOP THE APPLIANCE
For Short Periods
Turn the central heating temperature control knob fully anti-
clockwise past the position. NOTE: The appliance will still operate
in the domestic hot water mode.
For Long Periods
Turn the central heating temperature control knob fully anti-
clockwise past the position. Switch off the electricity at the mains
supply.
A facia mounted electronic programmer will retain its settings for
about two weeks, after which it will return to the factory set
programme. The time will be saved for approximately 7 hours. The
display will disappear after approximately 1 hour.
A facia mounted mechanical programmer will require resetting
once the central heating temperature control knob has been set fully
anti-clockwise past the position, or the 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.
OVERHEAT CUT-OFF
THERMOSTAT
The appliance will enter a lockout condition in the event of
overheating.
An overheat cut-off thermostat is fitted to the appliance which
will interrupt the electricity supply to the gas valve.
If the overheat cut-off has operated, the fault indicator will flash once
a second.
The appliance can be reset by pressing the fault indicator button
and holding in for 5 seconds when the appliance has cooled. If this
condition continues to occur, then call a service engineer.

11
IGNITION LOCKOUT
The appliance will enter a lockout condition in the event of the
burner failing to ignite. If the burner fails to light after 5 attempts the
electricity supply to the gas valve will be interrupted.
If ignition lockout has occurred, the fault indicator will flash
slowly (approximately once per second).
The appliance can be reset by ending the present demand which
in a central heating demand means turning the central heating
temperature control to ‘’and back to the required setting or ending
the room thermostat/programmer demand. In the domestic hot water
mode, turn the tap OFF and ON.
Re-ignition will be attempted after a delay of four minutes.
Domestic hot water demands do not have this delay.
Check that the gas supply has not been interrupted.
If this condition continues to occur, then call a service engineer.
AIR FLOW DEVICE
The appliance will enter a lockout condition in the event of an
air flow fault.
If the controls fail to detect the correct air flow through the
appliance the electricity supply to the gas valve will be interrupted.
If an air flow fault has occurred, the fault indicator will flash
(approximately five times per second).
The appliance will try to re-light after a waiting period of
approximately 5 minutes Check that the flue terminal has not been
obstructed or damaged.
If this condition continues to occur, then call a service engineer.

12
More than 30% of all calls made to Worcester Heat Systems to
report appliance faults or breakdowns prove to be false alarms, as there
is often a simple explanation for the apparent malfunction.
So, to help you save time and money – not to mention frustration
and inconvenience – please refer to the General Information, Notes and
Lighting Instructions ensuring all controls are set correctly.
If, after following the instructions the appliance still fails to operate
correctly call the Worcester Heat Systems Service Centre in Great Britain
or Eire. Arrangements will be made for an engineer to call as soon as
possible.
CALL-OUT CHARGES
All of our Field Service Engineers are factory trained.
If you request a visit from an engineer and your appliance has been
installed within the last 12 months, no charge will be made for parts
and/or labour, providing:
•The appliance was commissioned correctly on installation.
•An appliance fault is found and the appliance has been installed
within the past 12 months.
A call-out charge will be made where:
•The appliance has been installed for over 12 months, or
•Our Field Service Engineer finds no fault with the appliance (see
note), or
•The cause of breakdown is with other parts of your
plumbing/heating system, or with equipment not supplied by Worcester.
NOTE: Invoices for attendance and/or repair work carried out on
your appliance by any third party will not be accepted.
APPLIANCE FAILS TO
OPERATE

13
MAINTAINING YOUR
APPLIANCE
Your new Worcester ijunior 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 12 month
guarantee period.
Regular service contracts can be arranged with your installer
– however if you have difficulty making a satisfactory
arrangement simply contact Worcester Heat Systems on
08457 256206 or in Eire 01 494 0099 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.

CONTACT NUMBERS:
UK Call Centre Tel. [phone]
UK Call Centre Fax. [phone]
Scotland only Fax. [phone]
Eire Tel. [phone]
OPERATING HOURS:
Mon - Fri 8.00am to 6.00pm
Sat 8.30am to 1.00pm
Please contact our UK Call Centre number where our friendly operators
will book your call with one of our team of nationwide engineers.
NOTE:
Sunday and Bank Holiday cover is not available
14
SERVICE CENTRES

15
YOUR WORCESTER
ijunior SERIES
GUARANTEE
This appliance is guaranteed against faulty materials or
workmanship for a period of twelve calendar months from the
date of installation subject to the following conditions and
exceptions.
1. That during the currency of this
guarantee any components of the
unit which are proved to be faulty
or defective in manufacture will be
exchanged or repaired free of
material charges and free of labour
charges by Worcester Heat Systems
Limited.
2. That the householder may be asked
to prove the date of installation,
that the appliance was correctly
commissioned and, where
appropriate, the first 12 month
service has been carried out to the
satisfaction of Worcester Heat
Systems Limited when requested.
3. That any product or part thereof
returned for servicing under the
guarantee must be accompanied by
a claim stating the Model, Serial
Number, Date of Installation.
4. That Worcester Heat Systems
Limited will not accept
responsibility for damage caused by
faulty installation, neglect, misuse
or accidental damage, the non-
observance of the instructions
contained in the installation and
Operating Instructions Leaflets.
5. That the appliance has been used
only for normal domestic purposes
for which it was designed.
6. That this guarantee applies only to
equipment purchased and used in
mainland Great Britain.
This guarantee is given in addition to all your normal statutory rights.

Bosch Group
Heating & Hot Water Comfort
Worcester Heat Systems Limited. Cotswold Way, Warndon, Worcester WR4 9SW.
Telephone: [phone] Fax: [phone].
Technical Helpline GB [phone] Eire 01 494 0099.
8 716 105 874a 06/03
GUARANTEE
REGISTRATION
You should complete and return the postpaid Guarantee
Registration Card within 14 days of purchase.
The card will register you as the owner of your new
Worcester ijunior 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
Do not forget to keep the Log book
in a safe place.