Worcester GREENSTAR 24i junior User manual

UK/IE
USER INSTRUCTIONS
WALL HUNG RSF GAS FIRED CONDENSING COMBINATION BOILER
GREENSTAR 24i Junior/28i Junior
6720643356-00.1Wo
FOR SEALED CENTRAL HEATING SYSTEMS AND MAINS FED DOMESTIC HOT WATER
6 720 802 048 (2013/05)
The appliance is for use with Natural Gas or
L.P.G. (Cat II 2H3P type C13, C33 & C53)
Model GC Number
Natural Gas 24i Junior 47-406-54
28i Junior 47-406-56
Liquid Petroleum Gas 24i Junior 47-406-55
28i Junior 47-406-57

2
PREFACE
6 720 802 048 (2013/05)
PREFACE
PLEASE READ THESE INSTRUCTIONS CAREFULLY
These instructions are applicable to the Worcester, Bosch
Group boiler model stated on the front cover only.
These instructions apply in the UK/IE only and must be followed
except for any statutory obligation.
After installation please leave this User instruction Manual,
Installation, Commissioning and Servicing Instructions and
completed Benchmark Checklist with the user.
DEDICATED TO HEATING COMFORT
Thank you for purchasing a Greenstar gas-fired condensing
combination boiler manufactured by Worcester, Bosch Group.
The company prides itself on manufacturing boilers to the
strictest quality control standards throughout every stage of
production.
Worcester, Bosch group has led the field in innovative boiler
design and performance for over 50 years. This heritagemeans
all our products are of exceptional quality and proven
reliability.
The Greenstar range in particular is extremely energy efficient,
offering you economical running costs and value for money. It
sits in SEDBUK 2005 Band A and SEDBUK 2009 efficiency
rating of 89.1%, It is therefore amongst the top energy rated
boilers 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.

3
CONTENTS
6 720 802 048 (2013/05)
CONTENTS
1 Symbols and safety precautions . . . . . . . . . . 4
1.1 Explanation of symbols . . . . . . . . . . . . 4
1.2 Safety precautions . . . . . . . . . . . . . . . 4
2 General Information . . . . . . . . . . . . . . . . . . . . 5
3 Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1 Operating the boiler . . . . . . . . . . . . . . 7
3.1.1 Setting the central heating temperature
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1.2 Switch off the central heating . . . . . . 7
3.1.3 Boiler frost protection . . . . . . . . . . . . 7
3.1.4 Setting the hot water temperature . . 8
3.1.5 Domestic hot water pre-heat . . . . . . . 8
3.1.6 Boiler reset . . . . . . . . . . . . . . . . . . . . . 9
4 System Pressure . . . . . . . . . . . . . . . . . . . . . . 10
4.1 Sealed heating system . . . . . . . . . . . 10
4.2 Locating the integral filling link . . . . 10
4.3 Optional integral keyless filling link . 11
4.4 Optional integral keyed filling link . . 12
4.5 External filling loop . . . . . . . . . . . . . . 13
5 Service Clearances . . . . . . . . . . . . . . . . . . . . 14
6 Maintaining your Boiler . . . . . . . . . . . . . . . . 14
7 Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . 15
8 Fault or Breakdown . . . . . . . . . . . . . . . . . . . 16
9 Tips on energy saving . . . . . . . . . . . . . . . . . . 17
10 Your Guarantee . . . . . . . . . . . . . . . . . . . . . . . 18
11 Environment / disposal . . . . . . . . . . . . . . . . 18
12 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4
SYMBOLS AND SAFETY PRECAUTIONS
6 720 802 048 (2013/05)
1SYMBOLSANDSAFETY
PRECAUTIONS
1.1 EXPLANATION OF SYMBOLS
WARNING SYMBOLS
Signal words indicate the seriousness of the hazard in terms of
the consequences of not following the safety instructions.
•NOTICE indicates possible damage to property or
equipment, but where there is no risk of personal injury.
•CAUTION indicates possible personal injury.
•WARNING indicates possible severe personal injury.
•DANGER indicates possible risk to life.
IMPORTANT INFORMATION
ADDITIONAL SYMBOLS
1.2 SAFETY PRECAUTIONS
IF YOU SMELL GAS!
A gas leak could potentially cause an explosion. If you smell gas,
observe the following rules.
▶Preventflamesorsparks:
–Donotsmoke,usealighterorstrikematches.
–Donotoperateanyelectricalswitchesorunplugany
equipment.
– Do not use the telephone or ring doorbells.
▶Turnoffthegasatthemeterorregulator.
▶Open windows and doors.
▶Warnyourneighboursandleavethebuilding.
▶Preventanyonefromenteringthebuilding.
▶Wellawayfromthebuilding: call the National Gas
Emergency Service on 0800 111 999.
▶L.P.G.boilers:Callthesupplier’s number on the side of the
gas tank.
BOILER OPERATION:
This boiler must only be operated by a responsible adult who
has been instructed in, understands and is aware of the boiler's
operating conditions and effects.
COMBUSTIBLE AND CORROSIVE MATERIALS:
Chemically aggressive substances can corrode the boiler and
invalidate any warranty.
▶Donotstoreoruseanycombustiblematerials(paper,
thinners, paints etc.) inside or within the vicinity of the
boiler.
FITTINGS AND MODIFICATIONS:
Only a competent engineer in accordance with the Gas Safety
(Installation and Use) Regulations can remove the outer case
and carry out any work.
▶Do not remove the outer casing.
Any misuse or unauthorised modifications to the boiler, flue or
associated components and system will invalidate the
warranty.
▶Donotmodifytheboilerorfluesysteminanyway.
Worcester, Bosch Group accepts no liability arising from any
such actions. This does not affect your statutory rights.
Safety instructions in this document are
framed and identified by a
warning triangle which is printed on a grey
background.
Notes contain important information in
cases where there is no risk of
personal injury or material losses and are
identified by the symbol shown on the left.
They are bordered by horizontal lines above
and below the text.
Symbol Meaning
▶astepinanactionsequence
areferencetoarelatedpart in the document or to
other related documents
•alistentry
– a list entry (second level)
Table 1 Symbols

5
GENERAL INFORMATION
6 720 802 048 (2013/05)
2 GENERAL INFORMATION
SERVICING
▶Theboilermustbeservicedregularlybyacompetent,
qualified person, such as a Worcester service engineer or
other Gas Safe registered engineer.
▶Always use original spares, to help maintain the economy,
safety and reliability of the boiler and have the Service
Record completed in the Benchmark Checklist.
The completed Benchmark Checklist will be required in the
event of any warranty work and may be required by the local
Building Control Inspector.
BENCHMARK STANDARD
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 boiler. 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.
The log book provides space for the recording of regular
servicing of the boiler/system and this can become a valuable
document when, for example, the householder wishes to sell
the property. The log book will show a potential purchaser that
the heating system has received regular professional attention
during its lifetime.
The Benchmark initiative aims to:
• Raise standards among professional installers
• Build and maintain high safety standards in the industry
• Improve customer satisfaction levels
•Makeacontributiontothenation‘s commitment to “Climate
Change”
Ensure that the service engineer completes the
Service Record in the Benchmark Checklist
after each service. The Benchmark Checklist
and service interval record can be found at the
rear of the Installation, Commissioning and
Servicing Instructions.

6
CONTROLS
6 720 802 048 (2013/05)
3 CONTROLS
▶To gain access to the boiler controls push the top centre of the flap and release.
Fig. 1 Control panel fascia
Boiler
Controls
1Central heating temperature control 6 ECO button
2Burner indicator (Green) 7 Reset button
3Service button 8 Hot water temperature control
4Cover or optional Programmer 9 System pressure gauge
5Power ON and fault indicator (Blue)
12345678
6720643356-13.1Wo
9

7
CONTROLS
6 720 802 048 (2013/05)
3.1 OPERATING THE BOILER
3.1.1 SETTING THE CENTRAL HEATING TEMPERATURE
1. Turn the central heating temperature control knob to the desired level.
Temperatures given in the figure below are approximate.
2. The Burner indicator (green) will illuminate to show that the boiler is running.
Fig. 2 Central heating temperature control
3.1.2 SWITCH OFF THE CENTRAL HEATING
1. Turn the temperature control knob to the snowflake symbol to switch off the central heating.
Fig. 3 Switch off central heating
3.1.3 BOILER FROST PROTECTION
If the temperature within the boiler falls below 8°C the pump will run to circulate water and prevent the system freezing.If the
temperature within the boiler falls below 5°C the boiler will fire periodically, bringing the boiler temperature up to 12°C to avoid the
possibility of the system freezing.This process will be repeated until such time that the boiler temperature does not drop below 5°C.
Min
1
2
3
4
5
6
Max
---
---
---
---
---
---
---
---
40 °C
47 °C
53 °C
61 °C
68 °C
74 °C
80 °C
82 °C
1
2
34
5
6
max
6720643356-05.1Wo
1.
2.
1
2
34
5
6
max
reset
eco
1
2
34
e
6
maxmin
6720643356-06.1Wo
1.

8
CONTROLS
6 720 802 048 (2013/05)
3.1.4 SETTING THE HOT WATER TEMPERATURE
1. Turn the hot water temperature control knob to the desired level.
Fig. 4 Hot water temperature
3.1.5 DOMESTIC HOT WATER PRE-HEAT
The hot water heat exchanger is kept “pre-heated” to reduce the time taken to deliver hot water at the tap. Pre-heat is enabled by
default, during the initial boiler start up and the ECO button is not illuminated.
Eco mode is an energy saving function allowing hot water to be heated only as and when required, by running a hot tap, this OFF by
default.
1. Press and hold the Eco button for at least four seconds to enter the energy saving Eco mode, when Eco mode is active the Eco
button will be illuminated.
Fig. 5 Eco mode
1
2
34
5
6
max
reset
eco
1
2
34
e
6
maxmin
6720643356-07.1Wo
1.
1
2
34
5
6
max
reset
eco
1
2
34
e
6
maxmin
6720643356-08.1Wo
1.

9
CONTROLS
6 720 802 048 (2013/05)
3.1.6 BOILER RESET
In the event of a fault, the reset button will flash once per second and the blue mains indicator light will flash.
1. To reset the boiler press the reset button for approximately five seconds.
When the boiler resets the reset button will no longer be illuminated.
2. The mains indicator will no longer be flashing.
Fig. 6 Reset button and mains light
If the fault remains and cannot be cleared by pressing the reset button, contact Worcester, Bosch Group for
assistance.
1
2
34
5
6
max
reset
eco
1
2
34
e
6
maxmin
6720643356-09.1Wo
1.
2.

10
SYSTEM PRESSURE
6 720 802 048 (2013/05)
4SYSTEMPRESSURE
4.1 SEALED HEATING SYSTEMS
This boiler is fitted to a sealed heating system which is pre-pressurised. Your installer will advise you of the minimum and maximum
pressure indicated on the pressure gauge.
▶Checkregularlythatthepressureismaintained.
▶Ifthepressuregaugereadslessthan1bar then the system requires re-charging.
▶Contactyourinstallerormaintenanceengineerifapermanentsignificant decrease or increase in pressure is indicated on the
pressure gauge.
The filling method will be one of three types:
•Optional“Keyless”integralfillinglink
•Optional“Keyed”integral filling link
•Anexternalfillingloop,fitted valves and flexible hose.
4.2 LOCATING THE INTEGRAL FILLING LINK
To remove bottom panel:
1. Push the panel back fully to release the front edge
2. Pull forward and down to remove
Fig. 7 Remove the bottom panel
Fig. 8 Integral filling link location
1. 6720806709-01.1Wo
2.
67206800521-02.2Wo

11
SYSTEM PRESSURE
6 720 802 048 (2013/05)
4.3 OPTIONAL INTEGRAL KEYLESS FILLING LINK
Locate filling link and follow instructions for re-pressurising.
1. If the needle on the appliance pressure gauge reads less than 1 bar, re-charge the system.
2. Pull the blue lever down to start the filling process.
3. Monitor the pressure gauge on the boiler fascia.
Fig. 9 Keyless filling link
4. When the needle reaches between 1 to 1.5 bar on the gauge, release the blue lever to stop the filling process.
67206800521-06.2Wo
Min
1 bar
1.5 bar
Max
1
1.
2.
3.
4.

12
SYSTEM PRESSURE
6 720 802 048 (2013/05)
4.4 OPTIONAL INTEGRAL KEYED FILLING LINK
Locate filling key and follow instructions for re-pressurising.
1. Push the filling key firmly into the body of the filling link, ensuring the arrow on the key shaft lines up with the open padlock
symbol.
2. Turn the filling key to the right, to the stop, so the arrow now lines up with the closed padlock symbol. This bridges the gap
between the two sections of the filling loop.
3. Turn the white knob to the left, this will allow water to fill the system.
4. When the pressure, shown on the boiler fascia pressure gauge, reaches between the 1 and 1.5 bar marks (zone A), turn the white
knob to the right to close the valve. Do not overtighten.
5. Turn the filling key to the left, to the stop, so that the arrow lines up with the open padlock symbol and pull the key straight down
to remove. Please remember to store the key in the bottom panel.
Fig. 10 Keyed filling link
3.
2.
1.
6720643356-10.3Wo
4.
5.
2
3
1
04
bar
1
A
Min
1 bar
1.5 bar
Max

13
SYSTEM PRESSURE
6 720 802 048 (2013/05)
4.5 EXTERNAL FILLING LOOP
Once the external filling loop has been located, follow the instructions for re-pressurising the system.
1. Unscrew blanking cap.
2. Attach the hose to the valves, screw on hand-tight.
3. Turn the handle/screwdriver slot through 90° to open the valves.
4. The handle/screwdriver slot will be in-line with the valves
Fig. 11 External filling loop
5. When the pressure reaches between the 1 and 1.5 bar marks (zone A), turn the handle/screwdriver slot back, through 90°, to
close the valve.
6. The handle/screwdriver slot will be at 90° to the valves
7. Remove the hose and replace the blanking caps.
6720643356-12.2Wo
1. 2.
7.
3. 3.
4.4.
5.
5.
6.6.
2
3
1
04
bar
1
A
Min
1 bar
1.5 bar
Max

14
SERVICE CLEARANCES
6 720 802 048 (2013/05)
5 SERVICE CLEARANCES
Your installer will have provided adequate space around the boiler for safety and servicing access.
Fig. 12 Service clearances
6 MAINTAINING YOUR BOILER
Your new gas-fired boiler 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 Group service contract, please tick the appropriate box on your warranty
registration card.
If your gas-fired boiler should fail to operate correctly or requires servicing please contact Worcester, Bosch Group Appointments
Team (see rear cover for details).
Details of the boiler including the Gas Council number can be found under the controls covers flap on the boiler.
The Gas Council number is also listed on the front cover of your Installation, Commissioning and Servicing Instructions.
CAUTION: Restricted space.
The boiler may overheat.
▶Do not restrict this space with the addition of cupboards, shelves etc. next to the boiler.
+ 30 mm
above elbow
5 mm
600 mm
5 mm
200 mm
6720643356-01.1Wo

15
FAULT FINDING
6 720 802 048 (2013/05)
7 FAULT FINDING
If a boiler fault occurs, please read the following page thoroughly before contacting Worcester, Bosch Group.
EXTREME COLD WEATHER
In instances where the condensate pipe work is run external or in an unheated area, such as a garage, it can be at risk of freezing,
even if insulated.
A frozen condensate pipe will cause the boiler to shut down, and display a flashing Reset light on the control panel.
If the condensate pipe has frozen:
▶Locatetheblockage.
It is likely that the pipe is frozen at the most exposed point external to the building or where there is some obstruction to flow.
This could be the open end of the pipe, at a bend or elbow, or where there is a dip in the pipe in which condensate can collect.
The location of the blockage should be identified as closely as possible before taking further action.
▶Thawthefrozenpipe.
The pipe can be thawed by applying a hot water bottle, a microwaveable heating pack (the sort used for muscular aches and
pains) or a cloth soaked in hot water to the exterior of the pipe, close to the point of blockage. Hot water can also be poured onto
the pipe from a watering can or similar container.
▶Oncethepipehasbeenthawedtheboilermustbereset,press the reset button for five seconds and wait two to three minutes
for the boiler to restart.
▶If the boiler does not restart, contact Worcester’s Technical Support Team (0844 892 3366) for assistance.
▶Contactyourinstallerinordertofind a permanent solution to the problem.
Problem Cause Remedy
Desired room temperature is not
reached
Thermostatic radiator valve(s) set too low ▶Increase thermostatic radiator valve setting(s)
Temperature control for central heating
flow on boiler set too low
▶Increasecentralheatingflowtemperature
control setting
Air trapped in heating system ▶Bleedradiatorsandrecharge heating system
Desired room temperature
exceeded by large amount
Radiators are too hot ▶Turndownthermostaticradiatorvalves/room
thermostat
▶Reducecentralheatingtemperaturebyturning
down the Central Heating control on boiler
Heating stays on for too long Clock is incorrectly set ▶Checksettingandadjust
No ON/OFF mains indicator Momentary power failure ▶Switchoffboileratmasterswitch,waitafew
seconds then switch on again
Hot water temperature too lowTemperaturesettoolow ▶Checksettingandadjust
Water flow at tap too high ▶Reduceflowrateattap
Hot water temperature too high Temperature set too high ▶Checksettingandadjust
Water flow at tap too low ▶Increaseflowrateattap
WARNING: Falling hazard!
Failure to follow this guidance can result in personal injury.
▶Onlyattempttothawacondense pipe that is at ground level, which is easily accessible.
▶Never attempt to thaw a condense pipe which is at height.
CAUTION: Pipe damage
▶DO NOT use boiling water to thaw the condensate pipe!

16
FAULT OR BREAKDOWN
6 720 802 048 (2013/05)
8 FAULT OR BREAKDOWN
This boiler is supported in the UK and Eire by Worcester, Bosch Group.
Specialist Service Engineers are available to attend a breakdown occurring on this boiler.
•Nochargewillbemadeforpartsand/orlabourproviding:
A boiler 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.
•Acall-outchargewillbemadewhere:
–Theboilerhasbeeninstalledforover24months.
–Evidencecannotbeprovidedthatthefirst year service inspection has been carried out (i.e. an entry in the Benchmark
Checklist).
–OurFieldServiceEngineerfinds no fault with the boiler.
– The cause of breakdown is misuse or with other parts of your plumbing/heating system, or with equipment not supplied by
Worcester, Bosch Group.
TECHNICAL SUPPORT
In the event of a boiler fault or breakdown please contact Worcester, Bosch Group appointments team on 0844 892 3000.
Your advisor 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 boiler by any third party will
not be accepted.
No boiler fault is found on over 30% of all service calls.
In the case of a suspected fault, refer to the fault finding section of this guide.

17
TIPS ON ENERGY SAVING
6 720 802 048 (2013/05)
9 TIPS ON ENERGY SAVING
HEATING ECONOMICALLY
The boiler provides a high level of comfort whilst keeping gas consumption and the environment effects as low as possible.
The gas supply to the burner is controlled according to the level of demand for heat. The boiler operates 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 an even distribution of heat throughout the home. This means
that the boiler may stay on for relatively long periods of time but will use less gas than a boiler that continually switches on and off.
CENTRAL HEATING SYSTEMS WITH ROOM THERMOSTAT/THERMOSTATIC RADIATOR VALVES
With modern heating systems set around a 20 °C heat loss, the optimum setting for a condensing boiler will be approximately
between one and two on the central heating temperature control. The system must be balanced correctly and the radiators may
need upgrading. This allows the boiler to condense as much as possible for 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.
ROOM THERMOSTATS
Reducing the setting of the room thermostat by 1°Ccanreducefuelconsumptionbyupto10%.
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.
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
200 mm 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.
RADIATORS
If a radiator is sited underneath a window, its performance will be affected if the curtains are allowed to drape over the radiator.
Shelves fitted above or in front of the radiator should also be avoided.
It is advisable to manually adjust all thermostatic radiator valves every 2 - 3 months to prevent them sticking. Ensure radiator valves
are correctly set and not damaged.
DRAUGHTS
Try to ensure that draughts around doors, windows, letter boxes and keyholes etc. are
reduced by using a suitable draught excluder.
CURTAINS
Lined curtains, or heavier full length curtains can provide excellent insulation. However, always ensure that the curtains do not
drape over radiators.
WARNING: AIR VENTS
▶Donotblockorsealanyairventsthatareinstalledtoensure that the central heating boiler operates safely.

18
YOUR GUARANTEE
6 720 802 048 (2013/05)
10 YOUR GUARANTEE
This boiler is guaranteed against faulty materials or workmanship for a period of 2 years from the date of installation subject to the
following terms and conditions.
•Duringtheperiodofthisguaranteeanycomponentsoftheboilerwhich are proven to be faulty or defective in manufacture will
be exchanged or repaired free of charge by Bosch Thermotechnology Ltd.
•Thehouseholdermaybeaskedtoprovethedateofinstallation, that the boiler was correctly commissioned and, where
appropriate, the first year‘s service has been carried out to the satisfaction of Bosch Thermotechnology Ltd., when requested.
These should be part of the Benchmark Checklist.
•Theboilerhasbeenusedonlyforthenormaldomestic purposes for which it was designed.
This guarantee does not affect your statutory rights.
GUARANTEE REGISTRATION
Returning the card will register you as the owner of your new gas boiler and will assist us in maintaining an effective and efficient
customer service by establishing a reference and permanent record for your boiler.
FOR YOUR OWN RECORD:
Please ensure that the Benchmark Checklist has been completed by your installer or service engineer.
11 ENVIRONMENT / DISPOSAL
Environmental protection is a fundamental corporate strategy of the Bosch Group.
The quality of our products, their economy and environmental safety are all of equal importance to us and all environmental
protection legislation and regulations are strictly observed.
We use the best possible technology and materials for protecting the environment taking account of economic considerations.
PACKAGING
We participate in the recycling programmes of the countries in which our products are sold to ensure optimum recycling.
All of our packaging materials are environmentally compatible and can be recycled.
Model
Serial No.1)
1) See identity label on control panel/flap or Benchmark Checklist.
Type/size
Date of installation
Name of Installer
Telephone number of Installer
USED APPLIANCES
▶All Greenstar gas boilers are 100% recycleable.
The various assemblies can be easily dismantled and synthetic materials are marked accordingly. Assemblies
can therefore be sorted by composition and passed on for recycling.

19
GLOSSARY
6 720 802 048 (2013/05)
12 GLOSSARY
Central heating systems
All radiators must be heated at an even rate. If the top of a radiatoris 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. Should water leaks be found 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.
Pluming and Condensate drain
This is a condensing boiler and the flue terminal will, at times give out a plume of water vapour. This is quite normal.
The boiler produces condensate which is discharged regularly by a syphon within the boiler via a plastic pipe to a drain. This pipe
must not be blocked or altered in any way.
Room thermostat / programmer
A room thermostat / programmer must be fitted to control the central heating. This controls the times and temperatures of the
central heating, preventing the boiler from firing unnecessarily. Refer to the instructions supplied with the thermostat and
programmer for further information.
Thermostatic radiator valves
Thermostatic radiator valves must be fitted in sleeping accommodation. It is recommended that this type of valve is fitted to all but
one of the radiators. The remaining radiator, where the room thermostat is located, must be uncontrolled and left open.
Pump over run function
After the boiler has finished a demand for central heating or hot water, the pump continues to run for three minutes to dissipate the
heat from within the boiler.
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.
SEDBUK
Seasonal Efficiency of Domestic Boilers in the UK.

WORCESTER, BOSCH GROUP:
TECHNICAL SUPPORT: 0844 892 3366
APPOINTMENTS: 0844 892 3000
SPARES: 01905 752571
LITERATURE: 0844 892 9800
TRAINING: 01905 752526
SALES: 01905 752640
Worcester, Bosch Group
Cotswold Way, Warndon, Worcester WR4 9SW.
Tel. [phone]
Worcester, Bosch Group is a brand name of
Bosch Thermotechnology Ltd.
worcester-bosch.co.uk
Document No. 6 720 802 048 (2013/05)