Worcester Greenstar 12i System ErP User manual

UK/IE
USER MANUAL
WALL HUNG RSF GAS FIRED CONDENSING SYSTEM BOILER
GREENSTAR i SYSTEM
6720643356-00.1Wo
FOR CENTRAL HEATING SYSTEMS
6 720 644 864 (2013/08)

2
PREFACE
Greenstar i System – 6720644 864 (2013/08)
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 heritage means
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
Greenstar i System – 6 720 644 864 (2013/08)
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 Boiler reset . . . . . . . . . . . . . . . . . . 9
4 SYSTEM PRESSURE . . . . . . . . . . . . . . . . 10
4.1 Sealed heating system . . . . . . . . 10
4.2 External filling loop . . . . . . . . . . . 11
5 SERVICE CLEARANCES . . . . . . . . . . . . . 12
6 MAINTAINING YOUR BOILER . . . . . . . . . 12
7 FAULT FINDING . . . . . . . . . . . . . . . . . . . . 13
8 FAULT OR BREAKDOWN . . . . . . . . . . . . 14
9 TIPS ON ENERGY SAVING . . . . . . . . . . . 15
10 YOUR GUARANTEE . . . . . . . . . . . . . . . . . 16
11 ENVIRONMENT/DISPOSAL . . . . . . . . . . 16
12 GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . 17

4
SYMBOLS AND SAFETY PRECAUTIONS
Greenstar i System – 6720644 864 (2013/08)
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:
– Do not smoke, use a lighter or strike matches.
– Do not operate any electrical switches or unplug any
equipment.
– Do not use the telephone or ring doorbells.
▶ Turn off the gas at the meter or regulator.
▶ Open windows and doors.
▶ Warn your neighbours and leave the building.
▶ Prevent anyone from entering the building.
▶ Well away from the building: call the National Gas
Emergency Service on 0800 111 999.
▶ L.P.G. boilers: Call the supplier’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.
▶ Do not store or use any combustible materials (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.
▶ Do not modify the boiler or flue system in any way.
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
▶ a step in an action sequence
a reference to a related part in the document or to
other related documents
• a list entry
– a list entry (second level)
Table 1 Symbols

5
GENERAL INFORMATION
Greenstar i System – 6 720 644 864 (2013/08)
2 GENERAL INFORMATION
Servicing
▶ The boiler must be serviced regularly by a competent,
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
• Make a contribution to the nation‘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
Greenstar i System – 6720644 864 (2013/08)
3 CONTROLS
▶ To gain access to the boiler controls open the flap and release.
Fig. 1 Control panel fascia
12345678
6720643356-13.1Wo
9
Boiler
Controls
1Central heating temperature control 6 ECO button (non functional)
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) * Requires optional integral diverter kit to be
functional

7
CONTROLS
Greenstar i System – 6 720 644 864 (2013/08)
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
Greenstar i System – 6720644 864 (2013/08)
3.1.4 Setting the hot water temperature
1. Turn the hot water temperature control knob to the desired level.
2. The Eco button is non operational with this type of boiler.
Fig. 4 Hot water temperature
Optional integral diverter valve kit with cylinder temperature sensor is required to be able to set the hot water
temperature.
Otherwise the temperature is factory set to approximately 55°C.
1
2
34
5
6
max
reset
eco
1
2
34
e
6
maxmin
6720644864-01.1Wo
1.
2.

9
CONTROLS
Greenstar i System – 6 720 644 864 (2013/08)
3.1.5 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. 5 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
Greenstar i System – 6720644 864 (2013/08)
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.
▶ Check regularly that the pressure is maintained.
Fig. 6 Optimum pressure when cold (area A)
▶ Contact your installer or maintenance engineer if a permanent significant decrease in pressure is indicated on the pressure
gauge.
The filling method on the i System boiler will be an external filling loop, with fitted valves and a flexible hose. The filling loop should
ideally be located close enough to the boiler so that the pressure gauge can be monitored during filling.
6720643356-11.1Wo
2
3
1
04
bar
1
A
Min
1 bar
1.5 bar
Max

11
SYSTEM PRESSURE
Greenstar i System – 6 720 644 864 (2013/08)
4.2 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. 7 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

12
SERVICE CLEARANCES
Greenstar i System – 6720644 864 (2013/08)
5 SERVICE CLEARANCES
Your installer will have provided adequate space around the boiler for safety and servicing access.
Fig. 8 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

13
FAULT FINDING
Greenstar i System – 6 720 644 864 (2013/08)
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:
▶ Locate the blockage.
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.
▶ Thaw the frozen pipe.
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 ofblockage. Hot water can also be poured onto
the pipe from a watering can or similar container.
▶ Once the pipe has been thawed the boiler must be reset, 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.
▶ Contact your installer in order to find 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
▶ Increase central heating flow temperature
control setting
Air trapped in heating system ▶ Bleed radiators and recharge heating system
Desired room temperature
exceeded by large amount
Radiators are too hot ▶ Turn down thermostatic radiator valves/room
thermostat
▶ Reduce central heating temperature by turning
down the Central Heating control on boiler
Heating stays on for too long Clock is incorrectly set ▶ Check setting and adjust
No ON/OFF mains indicator Momentary power failure ▶ Switch off boiler at master switch, wait a few
seconds then switch on again
Hot water temperature too low Temperature set too low ▶ Check setting and adjust
Hot water temperature too high Temperature set too high ▶ Check setting and adjust
WARNING: Falling hazard!
Failure to follow this guidance can result in personal injury.
▶ Only attempt to thaw a condense 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!

14
FAULT OR BREAKDOWN
Greenstar i System – 6720644 864 (2013/08)
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.
• No charge will be made for parts and/or labour providing:
A boiler fault is found and the appliance has been installed within the guarantee period. Reasonable evidence of this must be
supplied on request. i.e. the Benchmark Checklist.
• A call-out charge will be made where:
– The boiler has been installed for longer than the guarantee period.
– Evidence cannot be provided that the first year service inspection has been carried out (i.e. an entry in the Benchmark
Checklist).
– Our Field Service Engineer finds 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.

15
TIPS ON ENERGY SAVING
Greenstar i System – 6 720 644 864 (2013/08)
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 °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.
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. Ensureradiator 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
▶ Do not block or seal any air vents that are installed to ensure that the central heating boiler operates safely.

16
YOUR GUARANTEE
Greenstar i System – 6720644 864 (2013/08)
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.
• During the period of this guarantee any components of the boiler which are proven to be faulty or defective in manufacture will
be exchanged or repaired free of charge by Bosch Thermotechnology Ltd.
• The householder may be asked to prove the date of installation, 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.
• The boiler has been used only for the normal domestic 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.
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

17
ENVIRONMENT/DISPOSAL
Greenstar i System – 6 720 644 864 (2013/08)
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.
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.

18
GLOSSARY
Greenstar i System – 6720644 864 (2013/08)
12 GLOSSARY
Central heating systems
All radiators must be 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. 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 ademand 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.

19Greenstar i System – 6 720 644 864 (2013/08)
Notes

WORCESTER, BOSCH GROUP:
TECHNICAL SUPPORT: 0844 892 3366
APPOINTMENTS: 0844 892 3000
SPARES: 0190 575 2576
LITERATURE: 0844 892 9800
TRAINING: 0190 575 2526
SALES: 0190 575 2640
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
6 720 644 864 (2013/08)