Worcester Greenstar Si Compact Series User manual

UK/IE
USER INSTRUCTIONS
WALL HUNG RSF GAS FIRED CONDENSING COMBINATION BOILER
Greenstar Si Compact
6720643358-00.1Wo
FOR SEALED CENTRAL HEATING SYSTEMS AND MAINS FED DOMESTIC HOT WATER
6 720 807278 (2013/05)
These appliances are for use with:
Natural Gas or L.P.G.
(Cat. II 2H 3P type C13, C33 & C53)
Model GC Number
Natural Gas 25Si Compact 47-406-50
30Si Compact 47-406-52
L.P.G. 25Si Compact 47-406-51
30Si Compact 47-406-53

2
PREFACE
Greenstar Si Compact – 6 720 807 278 (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 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 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 Si Compact– 6 720 807 278 (2013/05)
CONTENTS
1 Symbols and safety precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 Explanation of symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Safety precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3 Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1 Operating the boiler in standby . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1.1 Boiler display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1.2 Setting the boiler flow temperature for the central heating system . . . . . . . . . . . . . . . . . . . 9
3.1.3 Boiler frost protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1.4 Turning the central heating off during the summer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1.5 Setting the temperature for domestic hot water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1.6 Domestic hot water preheat (without fascia timer fitted or external timer connected) . . . 10
3.1.7 Domestic hot water eco mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
3.1.8 Domestic hot water preheat (with fascia timer fitted or external timer connected) . . . . . 11
3.1.9 Boiler alert state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1.10 Boiler reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1.11 Turn off the Operation/fault diagnostic light (blue) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4 System Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.1 Sealed heating systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.2 Locating the integral filling link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.3 Optional integral keyless filling link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
4.4 Optional integral keyed filling link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
4.5 External filling link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5 Service Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6 Maintaining your Boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7 Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
7.1 Extreme cold weather . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
8 Fault or Breakdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
9 Tips on energy saving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
10 Environment / disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
11 Your guarantee. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
12 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4
SYMBOLS AND SAFETY PRECAUTIONS
Greenstar Si Compact – 6 720 807 278 (2013/05)
1 SYMBOLS AND SAFETY 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.
IMPORTANT INFORMATION
ADDITIONAL SYMBOLS
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
1. a numbered step in an action sequence
▶ a step in an action sequence
a reference number to identify or refer to a part or item
•alistentry
– a list entry (second level)
1

5
SYMBOLS AND SAFETY PRECAUTIONS
Greenstar Si Compact– 6 720 807 278 (2013/05)
1.2 SAFETY PRECAUTIONS
IF YOU SMELL GAS
A gas leak could potentially cause an explosion. If you smell gas, observe the following rules.
▶ Prevent flames or sparks:
– 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 guarantee.
• Do not store or use any combustible materials (paper, thinners, paints, propellants, cleaning agents etc.) inside the cupboard
containing the boiler or within the vicinity of the appliance.
FITTINGS AND MODIFICATIONS:
Only a competent engineer can remove the boiler case and carry out any work, in accordance with the Gas Safety (Installation and
Use) Regulations.
• Do not remove the boiler case.
Any misuse or unauthorised modifications to the boiler, flue or associated accessories and heating system will invalidate the
guarantee.
• 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.
CLEANING THE BOILER CASE:
Use a damp, soft cloth to clean the outer painted metal case of the boiler, do not use chemicals or abrasive materials.

6
GENERAL INFORMATION
Greenstar Si Compact – 6 720 807 278 (2013/05)
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 efficiency, 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 guarantee 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 “checklist” is dispatched with every boiler and can be found towards the back of the Installation,
Commissioning and Servicing Instructions. 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 manufacturer's instructions.
The log book provides space for the recording of regular servicing of the boiler/heating system and this can become a valuable
document when, for example, you wish to sell the property. The log book will show a potential purchaser that the heating system
has received regular professional maintenance and servicing 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.

7
CONTROLS
Greenstar Si Compact– 6 720 807 278 (2013/05)
3 CONTROLS
▶ To gain access to the boiler controls pull the flap down using the curved flap handle.
Fig. 1 Basic boiler controls
Boiler
Controls
1Service menu/back button 9 Scroll down button
2Service engineer symbol = boiler is set to maximum
or minimum output for service
10 The blue light is ON when the boiler is in an
operational mode.
It will also flash to indicate a fault.
3Eco button
4Reset button 11 Position for optional programmer
5Boiler display 12 Hot water temperature control
6Central heating temperature control 13 Diagnostic port
(for Worcester service engineer use only)
7Scroll up button
8OK - Select/confirmation button 14 Central heating system pressure gauge
6720643358-02.1Wo
1 3 65 7 8 9 10 11 12 13 1442

8
CONTROLS
Greenstar Si Compact – 6 720 807 278 (2013/05)
DISPLAY SYMBOLS
SCREEN DISPLAY BRIEF DESCRIPTION EXPLANATION
All possible screen symbols This screen is displayed briefly during boiler start up
and shows all the symbols that could be displayed on
the screen.
Numerical display Displays a temperature setting or boiler status code.
Text display Display PreHeat or Eco, or the Alert code
Hot water Displays this symbol during a DHW demand.
Central Heating Displays this symbol during central heating demand.
Service engineer mode Displays during service when the boiler is set to
maximum or minimum output.
Alert Displays along with the boiler status code and
diagnostic code during a fault condition.
Service mode Displays when a qualified service engineer is in the
service menus.
Burner on The boiler is in operation and the flame is alight.
Centigrade indication Displays next to the temperature reading.
Confirmation This symbol confirms a manual change.
Maintenance codes A code displayed with an H and a number relates to a
maintenance issue. This is not a boiler fault but an
indication that something will need attention
concerning the boiler.
The example shown is H13 Service interval reached,
the boiler requires servicing.
Call your installer or Worcester Bosch Group to
organise a service visit.
°C
°
F
°C
°C
°F
H 13

9
CONTROLS
Greenstar Si Compact– 6 720 807 278 (2013/05)
3.1 OPERATING THE BOILER IN STANDBY
3.1.1 BOILER DISPLAY
This is typical of the display when the boiler is not supplying a central heating or hot water demand.
The display will not be backlit and the internal temperature of the boiler is indicated.
When a heat demand occurs and the boiler fires up, the flame symbol will be displayed.
3.1.2 SETTING THE BOILER FLOW TEMPERATURE FOR THE CENTRAL HEATING SYSTEM
1. Turn the central heating temperature control knob to the desired flow temperature between 30 and 82°C, this will be indicated
on the digital display. This is not the room temperature but the flow temperature through the radiators.
The “e” point provides guidance for the maximum temperature setting for optimum energy efficiency.
2. The radiator symbol will be displayed to confirm that the central heating setting is being changed.
3. After five seconds of inactivity the boiler display will return to the default screen or press to exit.
▶ Comfort levels within rooms should be controlled by your thermostatic radiator valves and/or room thermostat.
3.1.3 BOILER FROST PROTECTION
If you are leaving your property unoccupied during cold weather, please leave your programmer on constant and your room
thermostat set to 15°C.
▶ 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 does not rise to 9°C within 30 minutes of the pump operating, the boiler will fire up.
▶ If the temperature within the boiler falls below 5°C the boiler will fire immediately, bringing the boiler temperature up to 12°Cto
avoid the possibility of the system freezing.
▶ This process will be repeated until such time that the boiler temperature does not drop below 8°C.
max
min
2
3
1
04
bar
1
ok
eco
reset
e
max
min
°C
°F
PreHeat
°C
°F
PreHeat
6720643358-13.1Wo
ok
max
min
2
3
1
04
bar
1
ok
eco
reset
e
max
min
°C
°F
Eco
1.
6720643358-03.1Wo
°C
°F
Eco
2.
3.

10
CONTROLS
Greenstar Si Compact – 6 720 807 278 (2013/05)
3.1.4 TURNING THE CENTRAL HEATING OFF DURING THE SUMMER
▶ Turn your programmer/timer to the off position.
▶ Please refer to the programmer/timer manufacturer's instructions.
3.1.5 SETTING THE TEMPERATURE FOR DOMESTIC HOT WATER
1. Turn the hot water temperature control knob to the desired level between 40 and 60°C, this will be shown on the digital display.
2. The tap symbol will be displayed to confirm that the domestic hot water setting is being changed.
3. After five seconds of inactivity the boiler display will return to the default screen or press to exit.
3.1.6 DOMESTIC HOT WATER PREHEAT (without fascia timer fitted or external timer connected)
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 PreHeat is displayed.
In the PreHeat mode, if there has been no demand for hot water for 24 hours the boiler will save energy by suspending PreHeat until
there is a demand for hot water. At this time PreHeat mode is re-activated.
ok
max
min
2
3
1
04
bar
1
ok
eco
reset
e
max
min
°C
°F
Eco
°C
°F
1.
6720643358-05.1Wo
max
min
2
3
1
04
bar
1
ok
eco
reset
e
max
min
°C
°F
Preheat
6720643358-06.1Wo
°C
°F
PreHeat

11
CONTROLS
Greenstar Si Compact– 6 720 807 278 (2013/05)
3.1.7 DOMESTIC HOT WATER ECO MODE
Eco mode is an energy saving feature which disables the Pre-heat function:
By selecting Eco mode you will be using less energy, but will have to wait a little longer for hot water.
1. Press and hold for at least four seconds to enter the energy saving Eco mode, when Eco mode is active, “Eco” will be
displayed.
▶ To exit ECO mode and return to PreHeat, press and hold for at least four seconds, PreHeat will be displayed.
3.1.8 DOMESTIC HOT WATER PREHEAT (with fascia timer fitted or external timer connected)
When a twin channel programmer is fitted/connected, the PreHeat/Eco option can be selected via the programmer.
Eco mode timed by a programmer will be displayed as shown below (1). Refer to the programmer manual for details on how to set
the time periods.
eco
max
min
2
3
1
04
bar
1
ok
eco
reset
e
max
min
°C
°F
Eco
6720643358-07.1Wo
°C
°F
Eco
1.
eco
max
min
2
3
1
04
bar
1
ok
eco
reset
e
max
min
°C
°F
Eco
6720643358-08.1Wo
°C
°F
Eco
1
select select
set ?
advance advance
OK
heating hot water
on
once
timed
off
on
once
timed
off

12
CONTROLS
Greenstar Si Compact – 6 720 807 278 (2013/05)
3.1.9 BOILER ALERT STATE
In the event of an alert, a fault code and an alert symbol will be displayed on the boiler display, and the blue operation/fault
light will flash. Refer to the Fault finding section on page 18 or press to clear the problem.
3.1.10 BOILER RESET
1. To reset the boiler, press .
2. “Reset” and are briefly displayed.
▶ If the reset was successful the boiler will return to normal operation.
▶ If the reset was not successful then the alert code will be displayed again, and the blue operation/fault light will continue to flash.
3.1.11 TURN OFF THE OPERATION/FAULT DIAGNOSTIC LIGHT (BLUE)
Your new Greenstar boiler is designed to use as little electricity as possible during operation and in stand-by mode. To further
enhance your energy saving during stand-by, you may choose to deactivate the operation/fault diagnostic light. The light will still
flash to alert you to a possible fault, but will not activate during a demand for heat. Please ask your installer to set-up this feature.
If the fault remains and cannot be cleared by pressing the reset button, contact Worcester, Bosch Group for
assistance on 0844 892 3000.
reset
max
min
2
3
1
04
bar
1
ok
eco
reset
e
max
min
°C
°F
227
°C
°F
227
6720643358-14.1Wo
reset
max
min
2
3
1
04
bar
1
ok
eco
reset
e
max
min
°C
°F
Reset
6720643358-09.2Wo
°C
°F
Reset
1.
2.

13
SYSTEM PRESSURE
Greenstar Si Compact– 6 720 807 278 (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.
▶ Check regularly that the pressure is maintained.
▶ If the pressure gauge reads less than 1 bar then the system requires re-charging.
▶ Contact your installer or maintenance engineer if a permanent significant decrease or increase in pressure is indicated on the
pressure gauge.
The filling method will be one of three types:
• Optional “Keyless”integral filling link
• Optional “Keyed” integral filling link
• An external filling loop, fitted valves and flexible hose.
4.2 LOCATING THE INTEGRAL FILLING LINK
Removing the bottom panel:
1. Pull the catch down.
2. Slide the panel forward and down to remove
Fig. 2 Bottom panel
Fig. 3 Integral filling link location
6720646608-28.1Wo
2.
1.
67206800521-02.2Wo

14
SYSTEM PRESSURE
Greenstar Si Compact – 6 720 807 278 (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. 4 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.
If the pressure gauge reads more than 1.5 bar as a result of over filling, bleed one radiator until the pressure gauge
returns to between 1 and 1.5 bar.
67206800521-06.2Wo
Min
1 bar
1.5 bar
Max
1
1.
2.
3.
4.

15
SYSTEM PRESSURE
Greenstar Si Compact– 6 720 807 278 (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. 5 Keyed filling link
If the pressure gauge reads more than 1.5 bar as a result of over filling, bleed one radiator until the pressure gauge
returns to between 1 and 1.5 bar.
3.
2.
1.
6720643356-10.3Wo
4.
5.
2
3
1
04
bar
1
A
Min
1 bar
1.5 bar
Max

16
SYSTEM PRESSURE
Greenstar Si Compact – 6 720 807 278 (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. 6 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.
NOTICE: External filling loops
▶ If the filling loop does not look like the one shown in the figure below or you cannot find your filling loop, contact
your installer.
▶ To comply with Water Authority regulations you must disconnect the external filling loop after re-pressurisation.
If the pressure gauge reads more than 1.5 bar as a result of over filling, bleed one radiator until the pressure gauge
returns to between 1 and 1.5 bar.
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

17
SERVICE CLEARANCES
Greenstar Si Compact– 6 720 807 278 (2013/05)
5 SERVICE CLEARANCES
Your installer will have provided adequate space around the boiler for safety and servicing access.
Fig. 7 Service clearances
6 MAINTAINING YOUR BOILER
Your new Greenstar gas-fired combi boiler represents a long term investment in a reliable, high quality product.
Wipe the boiler casing with a soft clean cloth. Please do not use chemical cleaning products which may damage the paint finish.
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 two year guarantee
period.
If your Greenstar gas-fired boiler should fail to operate correctly or requires servicing, please contact the Worcester, Bosch Group
Appointments Team (see rear cover for details).
Details of the boiler including the Gas Council number can be found on the front cover of these User Instructions and on the boiler
identification label on the boiler fascia.
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.
* Minimum clearances to removable door
** Minimum clearance required for servicing
*** Height for either 60/100 flue or 80/125 flue
1060/1100mm***
880mm
300mm
400mm
170/210mm***
600mm**
5mm
5mm
200mm
20mm*
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18
FAULT FINDING
Greenstar Si Compact – 6 720 807 278 (2013/05)
7 FAULT FINDING
In the event that the boiler stops functioning or does not perform as expected, you can carry out a few simple checks. These checks
are some of the most common causes and are listed in the table below. Should the problem persist or if other alert codes are
displayed, then it will be necessary to contact the Worcester, Bosch Group.
Problem Cause Remedy
EA fault code flashing on
display
No gas supply/low gas supply pressure ▶ Contact your gas supplier.
Condensate outlet blocked ▶ If it is safe to do so, check your condensate pipe
outlet for blockages, such as ice or foreign
objects.
Flue blocked ▶ If it is safe to do so, check your flue outlet for
damage or blockages.
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 re-pressurise the heating
system
Low system water pressure ▶ Re-pressurise the system, refer to page 14
Low temperature setting on the boiler
controls
▶ Increase settings on boiler controls
Desired room temperature too
high
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 clock setting and adjust
No blue Operation/Fault
Indicator
Momentary power failure ▶ Disconnect boiler supply, wait a few seconds then
reconnect.
Energy saving feature is activated ▶ Ask your installer to reset the blue light
Hot water temperature too low Temperature set too low on boiler
controls
▶ Check setting and adjust
Water flow at tap too high ▶ Reduce flow rate at tap
Air trapped in heating system ▶ Bleed radiators and re-pressurise the heating
system
Low system water pressure ▶ Re-pressurise the system, refer to page 14
Hot water temperature too high Temperature set too high on boiler
controls
▶ Check setting and adjust
Water flow at tap too low ▶ Increase flow rate at tap
Table 1 Fault finding

19
FAULT FINDING
Greenstar Si Compact– 6 720 807 278 (2013/05)
ALERT CODES
If the blue operation/fault indicator light on the front of your boiler is flashing and a warning triangle is displayed with an alert
code on the screen, e.g. EA, reset your boiler, refer to page 12.
Press , if the reset has been successful the word Reset will be displayed with the tick mark to confirm that the reset was
successful.
After a few seconds of a successful reset the boiler display will return to a normal display, the display sequence is shown in figure 8
below.
Fig. 8 Resetting a fault condition
Due to the internal safety systems of your Greenstar Si Compact boiler, some codes cannot be cleared by a simple reset. Please
contact Worcester, Bosch Group for further assistance.
When calling Worcester, Bosch Group about a fault, it will be useful to quote the alert code and three digit number under the alert
code, e.g. EA and 227. If there is a fault that cannot be reset by you, the user, then a service engineer visit will be necessary.
7.1 EXTREME COLD WEATHER
In some instances where the condensate pipe work is run externally or in an unheated area, such as a garage, the condensate pipe
work can be at risk of freezing, even if well insulated.
A frozen/blocked condensate pipe will cause the boiler to shut down.
If the condensate pipe has frozen:
▶ Locate the blockage.
It is likely that the pipe is frozen at the most exposed point outside the building or where there is an obstruction to flow.
This could be the open end of the pipe, at a bend or elbow, or where there is a sag 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 of blockage.
Hot water, but not boiling, can also be poured onto the pipe from a watering can or similar container. Care must be taken at
pedestrian areas where this water may freeze and create a slip hazard.
▶ 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, Bosch Group Appointments Team on: 0844 892 3000.
▶ Contact your installer in order to find a permanent solution to the problem.
WARNING: Falling hazard!
Failure to follow this guidance may result in personal injury.
▶ Only attempt to thaw a condense pipe that is at ground level and easily accessible.
▶ Never attempt to thaw a condense pipe that is at height.
CAUTION: Pipe damage
▶DO NOT use boiling water to thaw the condensate pipe!
reset
6720643358-10.2Wo
°C
°F
Reset
°C
°F
Eco

20
FAULT OR BREAKDOWN
Greenstar Si Compact – 6 720 807 278 (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.
• No charge will be made for parts and/or labour providing:
A boiler fault is found and the boiler is 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 is outside 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 and bank holidays) 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.