Bosch WORCESTER Greenstar Heatslave II 12/18 User guide

UK
Installation, Commissioning and Servicing instruction manual
Floor Standing oil-fired Condensing Combination Boiler using Conventional
and Room Sealed Flue
Greenstar Heatslave II 2022+
12/18, 18/25 & 25/32
6720813344-05.1Wo
For fully pumped sealed central heating systems and mains pressure domestic hot water.
These appliances are for use with Kerosene (Class C2) only.
6 721 843 978 (2022/01) UK/IE

Contents
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01)2
Contents
1 Key to symbols and safety instructions . . . . . . . . . . . . . . . . . . . 3
1.1 Key to symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 General safety instructions . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Installation regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Complying with the building regulations . . . . . . . . . . . . . 5
3 Appliance information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.2 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.3 Energy efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.4 Layout & components . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4 Pre-Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1 Cleaning primary systems . . . . . . . . . . . . . . . . . . . . . . . 10
4.1.1 Before cleaning the system: . . . . . . . . . . . . . . . . . . . . . 10
4.1.2 Flushing the system . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1.3 Inhibitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1.4 Artificially softened water . . . . . . . . . . . . . . . . . . . . . . . 10
4.2 Mains supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2.1 Electrical supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2.2 Water supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.3 Oil supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.3.1 Single pipe gravity feed system: . . . . . . . . . . . . . . . . . . 11
4.3.2 Double pipe sub-gravity feed system: . . . . . . . . . . . . . 12
4.3.3 Single pipe suction lift with de-aerator: . . . . . . . . . . . . 12
4.3.4 Pipework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.3.5 Boiler isolation valve . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.4 Water systems and pipework . . . . . . . . . . . . . . . . . . . . 13
4.5 Condensate discharge . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.5.1 Condensate pipe work . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.5.2 Condensate production . . . . . . . . . . . . . . . . . . . . . . . . 15
4.5.3 Internal connections . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.5.4 External connections . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.6 Pressure relief pipework . . . . . . . . . . . . . . . . . . . . . . . . 18
4.7 Boiler locations and clearances . . . . . . . . . . . . . . . . . . 18
4.8 Flue gas system considerations . . . . . . . . . . . . . . . . . . 20
4.8.1 Combustion air quality . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.8.2 Flue terminal positions . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.9 Flue options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.9.1 Conventional flue (CF) . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.9.2 Room sealed flue options . . . . . . . . . . . . . . . . . . . . . . . 24
4.10 Plume management . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.1 Unpacking the boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.2 Pipework positions and flue opening . . . . . . . . . . . . . . 27
5.3 Boiler installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.4 Flue installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.4.1 Flue damper installation . . . . . . . . . . . . . . . . . . . . . . . . 29
5.4.2 Installation notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.5 Combustion chamber . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.6 Pipework connections . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.7 Oil burner and pump . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.8 Refitting components . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.9 Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.10 Electrical schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.11 Weather compensation . . . . . . . . . . . . . . . . . . . . . . . . . 37
6 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
6.1 Pre-commissioning checks-appliance . . . . . . . . . . . . . . 38
6.2 Filling the system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
6.3 Starting the appliance . . . . . . . . . . . . . . . . . . . . . . . . . . 39
6.3.1 Single pipe gravity feed systems: . . . . . . . . . . . . . . . . . 39
6.3.2 Double pipe sub-gravity feed systems and single pipe
suction lift with de-aerator: . . . . . . . . . . . . . . . . . . . . . . 39
6.3.3 Burner head setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
6.3.4 Boiler lockout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
6.3.5 Switching the appliance on/off . . . . . . . . . . . . . . . . . . . 41
6.3.6 Selecting Service Menus . . . . . . . . . . . . . . . . . . . . . . . . 43
6.3.7 Finish commissioning boiler checks . . . . . . . . . . . . . . . 44
6.4 Water treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
6.5 Finishing commissioning - Appliance . . . . . . . . . . . . . . 45
6.5.1 Appliance guarantee . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
7 Service and Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
7.1 Inspection and service . . . . . . . . . . . . . . . . . . . . . . . . . . 46
8 Fault finding and diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
8.1 Status cause codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
8.2 Information menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
8.3 Service menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
8.4 Factory reset and fault codes . . . . . . . . . . . . . . . . . . . . . 53
8.4.1 Factory reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
8.4.2 Locking or Blocking fault conditions . . . . . . . . . . . . . . . 53
8.4.3 Cause and fault codes . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
8.5 DHW function chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
8.6 CH function chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
8.7 Protection functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
8.8 Solar compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
8.9 Burner diagnostics mode . . . . . . . . . . . . . . . . . . . . . . . . 58
8.10 Riello digital control boxes . . . . . . . . . . . . . . . . . . . . . . . 59
8.10.1 Control box LED codes . . . . . . . . . . . . . . . . . . . . . . . . . . 59
8.10.2 Fault finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
8.11 Flame sensing photocell . . . . . . . . . . . . . . . . . . . . . . . . . 61
8.12 Oil supply vacuum testing . . . . . . . . . . . . . . . . . . . . . . . . 61
8.13 Air pressure switch, flue overheat reset and tank overheat
reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
8.14 Air pressure switch connections . . . . . . . . . . . . . . . . . . 62
8.15 System gassing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
8.16 Oil appliance commissioning checklist . . . . . . . . . . . . . 64
8.17 Service interval record . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Key to symbols and safety instructions
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01) 3
1 Key to symbols and safety instructions
1.1 Key to symbols
Warnings
The following keywords are defined and can be used in this document:
•NOTICE indicates a situation that could result in damage to property
or equipment.
•CAUTION indicates a situation that could result in minor to medium
injury.
•WARNING indicates a situation that could result in severe injury or
death.
•DANGER indicates a situation that will result in severe injury or
death.
Important information
Additional symbols
Examples of additional symbols used
A numbered step in an action sequence
A sequence of numbered steps or actions carried out in a specific order
to complete a task.
1. First action
2. Second action
3. Third action
etc.
A step in an action sequence
A sequence of defined actions or steps carried out in order to complete
a task.
▶Action
▶Nextaction
▶etc
A reference to a related part in the document or to other related
documents.
To refer the reader to a specific figure/table/section within the manual.
e.g. figure 1.
A reference number to identify or refer to a part or item.
In a related figure, items or parts identified by a sequential number.
List entries, first and second levels
• A single component/item
• A component/list, made up of multiple parts/items.
– Sub component or sub list of main component/list.
–etc.
Abbreviations used in this manual
Read these instructions before starting any installation
These instructions are applicable to the Worcester appliance model(s)
stated on the front cover of this manual only and must not be used with
any other make or model of appliance.
The instructions apply in the UK and Eire only and must be followed
except for any statutory obligation.
This appliance must be installed by a competent person, failure to install
correctly could lead to prosecution.
1.2 General safety instructions
These installation instructions are intended for heating engineers,
plumbers, and electricians.
▶ Read any installation instructions (boiler, heating controls, etc.)
carefully before starting the installation.
▶ Observe the safety instructions and warnings.
▶ Observe national and regional regulations, technical rules and
guidelines.
▶ Record all work carried out.
Electrical work
Electrical work must only be carried out by a qualified electrician:
▶ Before starting electrical work;
– Ensure that the electricity supply is safely Isolated and secured to
prevent inadvertent re-connection.
Information on safe isolation can be found in the Health and
Safety Executive guidance HSG85.
– Using test equipment approved to GS38 confirm that the
electricity supply is disconnected.
▶ Refer to the manufacturer’s information when installing other
components with Worcester equipment within the system.
Warnings in this document are identified by a warning
triangle printed against a grey background.
Keywords at the start of a warning indicate the type and
seriousness of the ensuing risk if measures to prevent
the risk are not taken.
This symbol indicates important information where
there is no risk to people or property.
Symbol Meaning
a numbered step in an action sequence
a step in an action sequence
a reference to a related part in the document or to other
related documents
a reference number to identify or refer to a part or item
a list entry
a list entry (second level)
Table 1 Symbols
1
ØDiameter
CH Central Heating
DHW Domestic Hot Water
DCW Domestic Cold water
HE Heat Exchanger
TRV Thermostatic Radiator Valve
IP Ingress Protection
CF Conventional Flue
RS Room Sealed
N/A Not Applicable
SEDBUK Seasonal Efficiency of Domestic Boilers in the UK
OFTEC Oil Firing Technical Association for the Petroleum Industry
IET Institution of Engineering and Technology
WRAS Water Regulations Advisory Scheme
LABC Local Authority Building Control Body
DWTA Domestic Water Treatment Association

Key to symbols and safety instructions
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01)4
Oil fumes or leaks from the appliance
If you smell oil fumes, observe the following rules.
▶ Extinguish any naked flames
▶ Isolate the electrical supply
▶ Isolate the fuel supply to the boiler
▶ Open windows and doors
▶ Rectify the fault
Health and safety
The appliance contains no asbestos and no substances have been used
in the construction process that contravene the COSHH Regulations
(Control of Substances Hazardous to Health Regulations). Where
applicable, the CE mark indicates compliance with relative EU
Directives.
Combustible and corrosive materials
Do not store or use any combustible materials (paper, thinners, paints
etc.) inside or within the vicinity of the appliance.
The combustion air must be kept clear of chemically aggressive
substances which can corrode the appliance and invalidate any
warranty.
Handling instructions and guidelines
It is advised that more than one person is involved in the transfer of the
packaged appliance from the van to the point of installation.
It is advised that no attempt should be made to move the packaged
appliance without the use of a suitable truck.
At all times the correct method for handling heavy objects should be
strictly observed.
▶ Lift only a manageable weight, or ask for help.
▶ When lifting, bend the knees, and keep the back straight and feet
apart.
▶ Do not lift and twist at the same time.
▶ Lift and carry items close to the body.
▶ Wear protective clothing and gloves to protect from any sharp edges.
Intended use
This boiler must only be used as a heat appliance in a heating system for
domestic purposes.
Any other use is considered inappropriate. Any damage that results from
such use is excluded from liability.
Appliance operation
This appliance can be used by children aged from 8 years
and above and persons with reduced physical, sensory or
mental capabilities or lack of experience and knowledge, if
they have been given supervision or instruction concerning
the use of the appliance, in a safe way, and understand the
hazards involved.
Children shall not play with the appliance.
Cleaning and user maintenance shall not be made by
children without supervision.
Installation, commissioning and servicing
Installation, commissioning and servicing must only be carried out by a
competent registered engineer.
▶ Only use original spares.
▶ Advise the user to have the system regularly serviced by a
competent, qualified engineer (such as OFTEC registered personnel)
using approved spares, to help maintain the economy, safety and
reliability of the appliance.
Fitting and Modification
Fitting the appliance and any controls to the appliance may only be
carried out by a competent engineer in accordance with these
instructions and the relevant Installation Regulations.
Flue systems must not be modified in any way other than as described in
the fitting instructions.
Any misuse or unauthorised modifications to the appliance, flue or
associated components and systems could invalidate the warranty. The
manufacturer accepts no liability arising from any such actions,
excluding statutory rights.
Handover to the user
When handing over, instruct the user how to operate the heating system
and inform them about its operating conditions.
▶ Explain how to operate the heating system and draw the user's
attention to any safety-relevant action.
▶ Explain that modifications and repairs must only be carried out by an
authorised contractor.
▶ Advise the user to have the system serviced annually by a competent,
qualified engineer, such as an OFTEC registered engineer.
▶ Leave the installation instructions with the completed
commissioning form with the homeowner.

Installation regulations
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01) 5
2 Installation regulations
2.1 Complying with the building regulations
This heating appliance forms part of the controlled services for the
building. It is law that all controlled services for buildings must comply
with building regulations. You must be able to satisfy your Local
Authority Building Control Body (LABC) that the work carried out
concerning the installation and commissioning of this heating appliance
has been carried out to a satisfactory standard.
OFTEC operate a competent persons scheme and registered installers
are able to certify that their work complies with building regulations.
Under the scheme;
• OFTEC must be informed about every installation.
• OFTEC will issue a building regulations compliance certificate to the
householder and will notify the LABC.
OFTEC provide controlled document forms CD10 and CD11 for use
during installation and commissioning respectively.
Other organisations operate self-certification schemes e.g. NAPIT and
BESCA Ltd. and it may be possible for installers who are members of
these organisations to self certify their work.
Alternatively you must submit a building control notice to the LABC
before installing any boiler. The LABC will then arrange regular
inspection visits during the work to ensure that the installation complies
with the regulations.
Installation
Failure to install appliances correctly could lead to prosecution.
The appliance should be installed by a competent person. The person
installing the appliance should be aware of the Health and Safetyat Work
Act and take appropriate action to ensure that the regulations are
adhered to. In order to give optimum efficiency and trouble free
operation the appliance must be commissioned by a qualified OFTEC
engineer.
The compliance with a British Standard does not, in itself, confer
immunity from legal obligations. In particular the installation of this
appliance must be in accordance with the relevant requirements of the
following British Standards and regulations in respect of the safe
installation of equipment:
The Building Regulations Part G, Part J and L1 England and Wales; Part
F, Part G and Part J Section III Scotland; Part L and Part F Northern
Ireland.
Local water company bye-laws.
The Control of Pollution (Oil) Regulations.
OFTEC Standards.
Where no specific instruction is given, reference should be made to the
relevant codes of practice.
Installations in Eire (Republic of Ireland)
The Installation must be performed by a competent and suitably trained
person in accordance with the following Eire regulations.
Current Building Regulations - Republic of Ireland
ETCI rules for electrical installation
For further guidance see:
OFTEC Technical book three - Regional requirements: Republic of
Ireland
BS 5410: part 1: Code of practice for Liquid Fuelled Boilers.
BS 799: part 5: Specification for Oil Storage Tanks
BS 7593: Code of Practice for treatment of water in
domestic hot water central heating systems.
BS 5449: part 1: Specification for forced circulation hot water
central heating for domestic premises.
BS EN 12828: Heating systems in buildings.
Design for water-based heating systems
BS 7291: Thermoplastic pipes and associated fittings for
hot and cold water for domestic purposes and
heating installations in buildings
BS 7074: part 1: Application, selection and installation of
expansion vessels and ancillary equipment for
sealed water systems.
BS 1254-2: Copper and copper alloys plumbing fittings part
2: Fittings with compression ends for use with
copper tubes.
BS 7671: IET Wiring Regulations, current edition.
BS 1362: Specification for general purpose fuse links for
domestic and similar purposes.

Appliance information
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01)6
3 Appliance information
3.1 General information
Standard package
Fig. 1 Standard package
[A] Floor standing oil fired condensing combination boiler for sealed
domestic central system heating and mains fed domestic hot
water.
[B] Flue damper
[C] ErP label
[D] Literature pack
Check List (Literature pack)
3.2 Technical data
Item Qty
Greenstar Heatslave II Installation/Servicing
Instructions
1
Users Instructions 1
Hardware Pack 1
Description Units 12/18 18/25 25/32
Central heating
Primary water capacity (total) litres 62 63 64
Available pump head (20°C
difference) at max. output
metres
water
4.7 4.0 4.2
Max. permissible system
operating pressure in accordance
with WRAS guidelines
bar 2.5 2.5 2.5
Flow restrictor colour Lime Beige Grey
Domestic Hot Water
Maximum flow rate (15%) litres/min 15 18 22
Minimum inlet pressure
(dynamic) for maximum flow rate
bar 1.5 1.2 1.6
Maximum hot water temperature
rise for 90 litres draw off (@max
flow rate)
°C 40 40 40
Flue
Exit flue gas mass flow kg/hr 29 40 51
6720821683-20.1Wo
DC
A
B
Pipework connections
Fuel line (compression) mm 10 10 10
CH flow mm 22 22 28
CH return mm 22 22 28
Water main inlet mm 15 15 15
DHW outlet mm 22 22 22
CH drain hose
connection
Condensate (polypropylene) mm 21.5 21.5 21.5
Electrical
Electrical power supply voltage AC. ..V 230 230 230
Frequency Hz 50 50 50
Sensors & Thermostats
CH control range °C 50/82 50/82 50/82
Slave tank control range °C 55/84 55/86 55/88
Boiler manual reset overheat set
point
°C 105 105 105
Flue manual reset overheat
thermostat set point
°C 110 110 110
Tank manual reset overheat
thermostat set point
°C 95 95 95
General data
Maximum hearth temperature °C <100 <100 <100
SEDBUK 2009 % 89.4 89.2 89.0
SEDBUK 2005 % 90.4 90.2 90.0
Appliance protection rating (with
programmer blanking plate
fitted)
IP 20 20 20
Appliance protection rating (with
fascia programmer fitted)
IP 20 20 20
Dry weight (excluding packaging) kg 124 126 128
Description Units 12/18 18/25 25/32

Appliance information
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01) 7
3.3 Energy efficiency
The following product data satisfy the requirements of the EU Regulations No. 811/2013 and No. 812/2013 supplementing Directive 2010/30/EU.
Product data
Symbo
lUnit 7731600260 7731600261 7731600262
Product type – – Greenstar Heatslave II 2022 +
12/18
Greenstar Heatslave II 2022 +
18/25
Greenstar Heatslave II 2022 +
25/32
Condensing boiler – – Yes Yes Yes
Low temperature boiler – – No No No
B1 boiler – – No No No
Cogeneration space heater (CHP) – – No No No
Combination heater – – Yes Yes Yes
Rated heat output Prated kW 18 25 32
Seasonal space heating energy efficiency s%92 92 92
Energy efficiency class – – A A A
Useful heat output
At rated heat output and high
temperature regime 1)
1) High temperature regime means 60 °C return temperature at heater inlet and 80 °C feed temperature at heater outlet.
P4kW 18.2 25.1 32.9
At 30 % of rated heat output and low
temperature regime 2)
2) Low temperature means for condensing boilers 30 °C, for low-temperature boilers 37 °C and for other heaters 50 °C return temperature (at heater inlet).
P1kW 5.6 7.8 10.0
Useful efficiency
At rated heat output and high
temperature regime 1) 4% 91.8 91.9 91.5
At 30 % of rated heat output and low
temperature regime2) 1% 98.5 97.8 97.3
Auxiliary electricity consumption
At full load elmax kW 0.165 0.159 0.150
At part load elmin kW 0.053 0.049 0.047
In standby mode PSB kW 0.002 0.002 0.002
Other items
Standby heat loss Pstby kW 0.166 0.159 0.161
Ignition burner power consumption Pign kW 0 0 0
Emissions of nitrogen oxides NOx mg/kWh 110 103 109
Annual energy consumption QHE GJ 57 79 103
Sound power level, indoors LWA dB(A) 56 56 55
Additional data for combination heaters
Declared load profile – – XL XL XL
Daily electricity consumption Qelec kWh 0.210 0.176 0.199
Annual electricity consumption AEC kWh 46 39 44
Daily fuel consumption Qfuel kWh 31.232 32.834 32.426
Annual fuel consumption AFC GJ 25 26 26
Water heating energy efficiency wh %66 63 64
Water heating energy efficiency class – – B B B
Table 2 Product data for energy consumption

Appliance information
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01)8
3.4 Layout & components
The diagram below excludes the top, front and RH side casing panels.
Fig. 2
1
6
2
7
3
4
89
510 11
12
13
14
15
18
19
16
17
20
21
22
23
24
25
26
27
C
A
B
28
29
30
31 32
33
34
35
36
37
39
38
41 44
42 43
47
46
45
a
40
6720821683-28.1Wo
48
52 49
51 50

Appliance information
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01) 9
A:
[1] CONTROL BOX ASSEMBLY
[2] SERVICE MODE BUTTON
[3] CH TEMPERATURE CONTROL KNOB
[4] LCD DISPLAY
[5] CASING SIDE PANEL
[6] FLUE "KNOCK-OUT" SECTION
[7] TANK TEMPERATURE CONTROL KNOB
[8] DIAGNOSIS PORT - WORCESTER ENGINEER
[9] SYSTEM PRESSURE GAUGE
[10] FLUE GAS SAMPLING POINT
[11] FLUE MANIFOLD COVER
[12] FLUE OVERHEAT THERMOSTAT PHIAL
[13] FLEXIBLE AIR DUCT (CONNECTING AIR INLET CASING TO AIR
INTAKE ON BURNER)
[14] CASING SUPPORT BRACKET
[15] SECONDARY HEAT EXCHANGER DRAIN
[16] HEAT EXCHANGER FLOW PIPE
[17] CONDENSATE OUTLET
[18] CONDENSATE TRAP
[19] CONDENSATE DRAIN PIPE
[20] FLEXIBLE CONDENSATE DRAIN PIPE CONNECTION
[21] OIL ISOLATING VALVE
[22] BASE PLATE AND OIL DRIP TRAY
[23] COMBUSTION CHAMBER ACCESS DOOR AND ONE PIECE
BAFFLE SET LOCATION
[24] PRIMARY HEAT EXCHANGER DRAIN
[25] EXPANSION VESSEL
[26] EXPANSION VESSEL BRACKET
[27] RIELLO RDB 2.2 BURNER
[28] HEATSLAVE TANK DRAIN
[29] HEATSLAVE TANK
[a] OPTIONAL FASCIA MOUNTED PROGRAMMERS AVAILABLE
(not supplied with the appliance)
B:
[30] CIRCULATING PUMP
[31] MANUAL RESET TANK OVERHEAT THERMOSTAT
[32] DRAIN POINT
[33] DIVERTER VALVE ASSEMBLY
[34] AUTOMATIC AIR VENT
C:
[35] DHW FLOW TURBINE
[36] TANK TEMPERATURE SENSOR (NTC)
[37] DHW HEAT EXCHANGER
[38] MAINS INLET TEMPERATURE SENSOR (NTC)
[39] DHW PRESSURE RELIEF VALVE
[40] DHW TEMPERATURE SENSOR (NTC)
[41] PRIMARY MANUAL AIR VENT
[42] FLOW TEMPERATURE SENSOR (NTC)
[43] SECONDARY HEAT EXCHANGER MANUAL AIR VENT
[44] PRIMARY HEAT EXCHANGER SAFETY SENSOR (NTC)
[45] SECONDARY HEAT EXCHANGER MANUAL AIR VENT
[46] PRESSURE RELIEF VALVE
[47] SECONDARY HEAT EXCHANGER
[48] CROSS BRACE
[49] FIRE VALVE SENSOR CLIP
[50] AIR PRESSURE SWITCH
[51] AIR PRESSURE SWITCH RESET
[52] FLUE OVERHEAT THERMOSTAT RESET
All the following Pre-Installation sections must be read
and requirements met before starting boiler or flue
installation.
CAUTION: Isolate the mains supplies before starting any
work and observe all relevant safety precautions.

Pre-Installation
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01)10
4 Pre-Installation
4.1 Cleaning primary systems
4.1.1 Before cleaning the system:
▶ Ensure that the system and pipe work is in good working order.
▶Where possible keep the existing appliance/circulating pump in
place when flushing the system.
Follow the guidance of BS7593:
Treatment of water in domestic hot water central heating and also the
flushing guidelines below.
4.1.2 Flushing the system
▶ Fill the system with cold water and check for leaks.
▶ Open all drain cocks and drain the system.
▶ Close drain cocks and add a suitable flushing agent at the correct
strength for the system conditions in accordance with the
manufacturer‘s instructions.
▶ Circulate the flushing agent before the boiler is fired up.
▶ Run the boiler/system at normal operating temperature as directed
by the manufacturer of the flushing agent.
▶ Drain and thoroughly flush the system to remove the flushing agent
and debris.
▶ It may be necessary to use a power flushing machine to aid the
cleansing procedure in some circumstances.
▶ Close the drain cocks and manual air vents.
▶ Add a suitable inhibitor to the system in accordance with the
manufacturers instructions.
▶ Fill the system to between 1 and 1.5 bar via a WRAS approved filling
loop.
▶ Vent any air from the boiler and system.
4.1.3 Inhibitor
Add a suitable inhibitor or combined inhibitor/anti-freeze, if the system
is exposed to freezing conditions, to the heating system in accordance
with the DWTA code of practice and inhibitor manufacturer‘s guidelines.
Water treatment products
Suitable water treatment products can be obtain from the following
manufacturers:
4.1.4 Artificially softened water
It is possible to have an ion exchange water softener fitted to the cold
water system of the property. However, the boiler requires an untreated
cold water connection taken from the mains supply, before the water
softener, to the primary water filling point of the heating system.
Alternatively there are water softening/treatment devices that do not
adjust or alter the pH levels of the water. With these devices it may not
be necessary to provide an untreated water by-pass to the primary water
filling point of the heat system.
4.2 Mains supply
4.2.1 Electrical supply
• Supply: 230 V - 50 Hz
• Cable: PVC insulated 0.75mm2 (24 x 0.2mm) temperature rated to
90°C. to BS EN50525.
• External 5A fuse to BS1362.
• The appliance must be earthed.
• This appliance must not be connected to a three phase supply.
• IPX4D.
• The wiring between the appliance and the electrical supply must
comply with the latest IET wiring regulations that apply to wiring a
fixed appliance.
• Any additional components that are connected to the boiler with
mains electrical supply must not have a separate supply.
4.2.2 Water supply
The following are general requirements and if necessary the advice of
the local water company should be sought before fitting the appliance.
• The appliance cold water supply should be the first connection off
the water main where possible.
• The appliance will accept pre-heated hot water to a maximum of
60°C
DANGER: Danger to life through electric shock!
▶ Before carrying out any work on electrical
components, isolate them from the power supply
(230 V AC) (fuse, circuit breaker) and secure against
unintentional reconnection.
NOTICE: Risk of damage to appliance or accessories!
▶ All the following pre-installation sections must be
read and requirements met before starting the
appliance or flue installations.
NOTICE: Risk of damage to system or appliance!
Debris from the system can damage the appliance and
reduce efficiency. Failure to comply with the guidelines
for the use of water treatment with the appliance will
invalidate the appliance guarantee and contravene the
Building Regulations.
▶ It is a requirement of the Building Services
Compliance Guide which is a second tier document
to the Building Regulations to flush and inhibit the
primary water system in accordance with BS 7593.
▶ The Building Services Compliance Guide
recommends that a primary water cleanser is fitted
to the system.
▶ Worcester recommends fitting a filter that will help
remove both magnetite and non-magnetic debris.
The inhibitor or combined inhibitor/anti-freeze must not
cause damage to the materials within the boiler (mild
steel, stainless steel, copper and brass) and any other
materials/components within the system.
▶ The concentration level of inhibitor in the system
should be checked every 12 months or sooner if
system content is lost.
WARNING: Sealing agents
▶ In cases where all attempts to find a system micro
leak have failed, Worcester, Bosch Group supports
the use of Fernox F4 leak sealer.
ADEY 01242 546700 - www.adey.com
FERNOX 0330 100 7750 - www.fernox.com
SENTINEL 01928 704330 - www.sentinelprotects.com/uk
NOTICE:
▶ Salt based, softened water must not be used to fill
the central heating system.

Pre-Installation
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01) 11
Mains water pressure
• Maximum mains fed water pressure 10 bar. If necessary, fit a
pressure reducing valve.
• Where the water main supply has a non-return, back flow prevention
valve fitted, a mini expansion vessel (A) must be connected to the
mains water inlet pipe (B) between the non-return valve (C) and the
boiler (D) as shown below.
Fig. 3 Mains expansion vessel
[A] Mini expansion vessel
[B] Mains water inlet
[C] Non return valve
[D] Boiler
Use in hard water areas
Normally there is no need for water treatment to prevent scale formation
as the maximum temperature of the heat exchanger is limited by the
electronic control circuit.
In areas where the temporary water hardness exceeds 200ppm,
consideration may need to be given to the fitting of a scale prevention
device. In such circumstances, the advice of the local water authority
should be sought.
4.3 Oil supply
•This appliance is suitable for Kerosene (Class C2) only, no other
fuel must be used.
• Plastic or steel tanks should be installed to BS 5410.
A steel tank should conform to BS 799: part 5 and have a slope of
1:24 away from the outlet with a sludge cock at the lower end.
•Do not use galvanised steel tanks or pipework for the oil system.
•Do not use soldered joints on the oil supply pipework.
4.3.1 Single pipe gravity feed system:
The oil storage tank [1] must be positioned so that the oil level does not
exceed 4 metres above the level of the burner oil pump [9] and in
addition the oil level must be at least 300mm above the oil pump [9].
Where the maximum oil level in the oil storage tank exceeds 4 metres, a
head breaking device must be installed between the tank [1] and the
burner oil pump [9].
Fig. 4 Single pipe feed
Maximum pipe run for single pipe gravity fed system
NOTICE: Boiler damage
▶ Non-return, back flow prevention devices (including
those associated with water meters) fitted to the
mains water supply can cause a pressure build up
which could damage the boiler and other household
appliances.
Minimum dynamic mains water pressure for maximum
performance
12/18 18/25 25/32
1.5bar 1.2bar 1.6bar
NOTICE: Contaminated oil supplies can damage the
appliance.
Failure to ensure that the oil supply is clear of
contaminants may invalidate the appliance warranty.
▶ Ensure the oil supply is free of contaminates and
measures are taken to prevent contamination of the
appliance.
NOTICE: Liquid fuel supply pipes should be provided
with mains equipotential bonding in accordance with
BS 7671.
6720805209-84.1Wo
A
BC
D
Key to Oil supply illustrations, figures 4, 5 & 6
1 Oil storage tank
2 Full base (plastic tank)
3 Isolating valve
4 Oil strainer and water separator
5 Fire valve to BS 5410
6Externalwall
7 Oil filter (70μm max filtration size)
8 Fire valve sensor
9Oilpump
10 Oil burner
11 Non-return valve
12 De-aerator
13 Appliance isolation valve
14 Sleeve
Table 3 Key to oil supply feed system
All dimensions are in metres unless otherwise stated.
The maximum pipe run figures are based on using
copper pipe with an inside diameter of 2mm less than
the outside diameter.
Head (m) 10mmØ 12mmØ Head (m) 10mmØ 12mmØ
0.5 12 30 2.5 62 100
1.0 25 69 3.0 74 100
1.5 37 91 3.5 87 100
2.0 49 100 4.0 99 100
6720813284-08.3Wo
1
23 4
300mm Min.
4m Max.
6 8
53
109
13
714
14

Pre-Installation
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01)12
4.3.2 Double pipe sub-gravity feed system:
Maximum suction height 3.5 m. Non-return valves must be fitted to the
inlet and return oil line between the oil pump [9] and oil storage tank [1].
Fig. 5 Double pipe feed
Maximum pipe run for double pipe sub-gravity fed system
4.3.3 Single pipe suction lift with de-aerator:
Maximum suction height 3.5 metres. The oil tank [1] must be positioned
below the oil pump [9]. Create an inlet and return loop between the de-
aerator [12] and oil pump [9].
A non-return valve must be incorporated within the de-aerator or fitted
to the oil line between the oil storage tank [1] and the de-aerator [12].
A top feed oil tank fitted with a de-aerator using an internal non-return
valve should have any non-return valves fitted in the base of the tank to
the suction line removed to assist purging air from the oil line.
Fig. 6 De-aerator feed
Maximum pipe run for single pipe suction lift with de-aerator
4.3.4 Pipework
▶ Refer to the oil supply sections Single pipe gravity feed
system: 4.3.1, Double pipe sub-gravity feed system: 4.3.2 & Single
pipe suction lift with de-aerator: 4.3.3 for oil supply pipework
configurations.
Oil supply pipework considerations:
• Lay the oil supply pipe as straight and level as possible to avoid air
pockets and unnecessary friction losses.
– Route away from the boiler access door or other hot surfaces.
• Install a manual isolating valve to the oil supply pipe, as close to the
oil storage tank as possible.
• Fit an oil strainer and water separator to the oil supply pipe, near the
oil storage tank.
– Fit an additional oil filter (70 μm max filtration size) close to the
boiler, but not inside the boiler casing.
• Fit a fire valve in accordance with BS 5410.
– The fire valve should be fitted externally to the building with the
fire valve sensor located within the appliance case.
– A fire valve with a shut off temperature of 85°C or higher must be
fitted to avoid the possibility of nuisance shut offs.
– A capillary type valve provides a neat and simple installation.
Alternatively, a fusible link or electrical system may be used.
• Under no circumstances should a combination isolating/fire valve be
used as the sole fire protection device.
4.3.5 Boiler isolation valve
▶ Use copper pipe of the correct diameter according to the information
shown in oil supply sections 4.3.1, 4.3.2 & 4.3.3.
– If using soft copper pipe (R220) with a compression fitting, an
insert must be used to prevent the pipe from collapsing or
distorting when the fitting is tightened.
▶ Slide nut [1] and olive [5] onto the oil supply pipe [4].
▶ Slide insert [3] into the pipe.
▶ Offer the pipe to the fitting [2] and tighten the nut [1].
Fig. 7 Isolation valve bracket removed for clarity
▶ Use flexible hoses to connect to the oil pump.
Head (m) 10mmØ 12mmØ Head (m) 10mmØ 12mmØ
050100 2.0 26 66
0.5 44 100 2.5 20 50
1.0 38 95 3.0 14 37
1.5 32 80 3.5 8 22
FUEL FLOW RATE
2.5kg/h 5kg/h 10kg/h 10kg/h
Head (m) 8mmØ 8mmØ 8mmØ 10mmØ
010055 26 100
0.5 95 45 23 100
1.0 80 40 20 90
1.5 70 35 17 75
2.0 60 30 14 65
2.5 45 25 11 50
3.0 35 15 8 35
3.5 25 10 5 20
The table and illustration above is a guide only and does
not in any way override the de-aerator manufacturer’s
instructions
3.5m Max.
150mm
6720813284-09.2Wo
1
23 4
73
6 8
5
11
109
13
14
14
6720813284-10.2Wo
24
3.5m Max.
1 6
12
5
33 7
109
8
13
14
14
6720813288-03.1Wo
1
5
4
3
2

Pre-Installation
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01) 13
4.4 Water systems and pipework
Primary system plastic pipework
• Any plastic pipework used for the CH system must have a polymeric
barrier, complying with BS 7291 and installed to BS 5955 with
1000mm (minimum) length of copper or steel pipe connected to the
boiler.
• Plastic pipework used for underfloor heating must be correctly
controlled with a thermostatic blending valve limiting the
temperature of the circuits to approximately 50°C with 1000mm
(minimum) length of copper or steel pipe connected to the boiler,
and a 20 K differential must be maintained at the appliance.
Primary system/connections/valves
• Do not use galvanised pipes or radiators.
• All system connections, taps and mixing valves must be capable of
sustaining a pressure of 3 bar.
• Radiator valves should conform to BS 2767:10.
• All other valves should conform to BS 1010.
• An automatic bypass valve must be connected between the heating
flow and return where TRVs are used on all radiators, fitted to give at
least a 3 metre circuit when activated.
• Drain cocks are required at all the lowest points on the system.
• Air vents are required at all high points on the system.
Sealed primary system
• Where the system volume is more than 180 litres at 0.5 bar or
exceeds 2.65 bar at maximum heating temperature an extra
expansion vessel (B) must be fitted as close as possible to the
appliance in the central heating return.
• Pressurise the extra expansion vessel (B) to the same figure as the
expansion vessel (A) built into the appliance.
Fig. 8 Combi boiler sealed system layout
[A] Expansion vessel
[B] Extra expansion vessel
[C] Automatic bypass valve
[D] Drain cock
[E] Appliance
[L] Lockshield valve
[R] Radiators
[T] Thermostatic radiator valve TRV
[U] To filling system
Filling primary sealed systems
• Filling the system must comply with the method shown in the figure
below.
• The filling point must be at low level and must never be a permanent
connection to the mains water supply.
• Filling loops must be WRAS approved.
Fig. 9
[CV] Check valve
[SV] Stop valve
Fig. 10
The boiler should not be allowed to operate with a return
temperature of less than 30°C when the system is up to
operating temperature.
Oil burners cannot modulate to accommodate a
reduction in heating loads. If the heating load can be
significantly reduced due to TRV’s or zoning of the
heating circuits, consideration should be given as to how
short cycling of the burner could be prevented. Burner
run times should remain greater than 2 minutes during
normal operation. A buffer vessel or thermal store
should be considered to prevent excessive short cycling
of a single appliance, or a low loss header could be used
to divide the heating duty between multiple lower output
appliances.
Filling the system
▶ The system must not be filled with salt based,
softened water.
D
R R
R R
B
P
D
C
TLTL
TL LL
A
U
E
6720805209-82.1Wo
SYSTEM FILL
SV SV
Test point
Temporary hose
Hose union CV
CV
Heating
return
Mains
supply
Greenstar Heatslave II
oil fired
combination boiler
Hot water supply
to property
Mini expansion
vessel
(0.75ltr capacity)
Balanced cold water
supply to property
3 bar pressure
reducing
valve
MCW
Check valve/
non return valve
Incoming
mains
stop valve
Blending valve
set to 60°C
6720805209-83.1Wo

Pre-Installation
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01)14
Showers/Bidets:
• If a shower head can be immersed in water or comes closer than
25mm from the top edge of a bath or shower tray spill over level then
an anti-siphon device must be fitted to the shower hose.
Only thermostatically controlled showers are suitable for use with
this appliance.
• Bidets with direct hot & cold mains water can be used (with the
approval of the local water authority) and must be the over rim
flushing type with shrouded outlets to prevent the fitting of hand held
sprays.
Domestic hot water:
Plastic pipework
• Any plastic pipework used for the DHW system must have a
polymeric barrier, complying with BS 7291 and installed to BS 5955
with 1000mm (minimum) length of copper or stainless steel pipe
connected to the boiler.
• Before installing plastic pipework, the pipe manufacturer’s literature
should be consulted.
• To prevent the temperature & pressure exceeding the limits advised
by the pipe manufacturer, a pressure reducing valve must be used to
prevent the incoming water pressure exceeding 3 bar (maximum).
Also a mini expansion vessel must be fitted to absorb the expanding
water and a blending valve set to 60°C must be fitted before the DHW
plastic pipework.
• When selecting plastic pipework for use with domestic water supply,
it should be ensured that it is compliant with all current local &
national legislation & regulations, including building regulations part
G, BS 7291 - 1,2 & 3, BS 8000 - 15 and information.
General:
• Taps and mixing valves must be capable of sustaining a pressure up
to 10 bar in accordance with the Water Regulations as they will be
operating at mains water pressure.
• Hot water temperature and flow rate are affected by the size and
insulation of pipework making up the distribution system and are
controlled by the hot water tap and the water main inlet pressure. A
mixing valve can be fitted if a more permanent setting is required.
• If using more than one outlet at once causes water flow starvation, fit
flow balancing valves or Ball-O-Fix valves to the appropriate outlets.

Pre-Installation
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01) 15
4.5 Condensate discharge
For correct installation and trouble free operation of the appliance the
following advice should be followed:
1. To minimise the risk of freezing, wherever possible, the
condensate drain should be installed internally.
2. All condensate pipework must ‘fall’ from the appliance by a minimum
of 3 ° (52mm per metre) to ensure adequate condensate flow.
3. The pipework route must allow air to be supplied back to the
appliance for correct operation of the condensate trap.
4. Connection to a rainwater down pipe must include an air break.
Also:
• Assessment of the risk of the condensate pipe freezing must be
carried out and appropriate precautions taken where necessary. This
must take into account the specific site conditions.
• The condensate pipework connected to the condensate drain outlet
on the appliance should have a minimum internal diameter (ID) of
19mm.
• Keep external pipework as short as possible.
Further precautions against freezing must be taken if external pipe
runs exceed 3m.
• External pipework should be increased to a minimum internal
diameter (ID) of 30mm and ideally be insulated.
• Minimise the number of bends and connectors.
• Remove burrs after cutting pipe.
• Remove surplus solvent from the interior of the pipe.
• The condensate pipework shall be run in polypropylene (PP).
4.5.1 Condensate pipe work
4.5.2 Condensate production
When the appliance is in operation it can produce between 10 to 15
litres of condensation per hour.
4.5.3 Internal connections
Soil stack connection
figure 11
In order to minimise risk of freezing during prolonged cold spells, the
following methods of installing condensate drainage pipe should be
adopted, in order of priority.
Wherever possible, the condensate drainage pipe should be routed and
terminated so that the condensate drains away from the boiler under
gravity to a suitable internal foul water discharge point such as an
internal soil and vent stack. A suitable permanent connection to the foul
waste pipe should be used.
Fig. 11 Disposal to soil vent stack
[1] Condensate discharge from appliance
[2] Soil and vent stack
[3] Minimum 450mm and up to three storeys
Waste pipe connection
figure 12
Alternatively if the first option is not possible an internal kitchen,
bathroom or washing machine waste pipe etc. can be used.
Ensure that the condensate drain pipe is connected “down stream” of
the waste trap and that the condensate drain enters into the top of the
pipe using a swept tee.
Fig. 12 Disposal to a waste pipe
[1] Condensate discharge from the appliance
[6] 75mm sink waste trap
Full details on condensate discharge.
▶ Follow the latest version of BS6798 and HHIC
guidance.
NOTICE: General considerations
▶ Where a new or replacement appliance is being
installed, access to an internal “gravity discharge”
point should be one of the factors considered in
determining boiler location.
▶ Condensate pipe connection at the appliance:
The plastic condensate pipe must have a nominal
outside diameter 22mm Ø .
▶ Ensure there are no blockages in the pipe run.
▶ Ensure that the discharge method for the installation
can effectively handle the condensate waste from the
appliance.
NOTICE: Unheated internal areas.
The condensate discharge may freeze in areas during
prolonged cold temperatures.
▶ Internal pipe runs in unheated areas such as lofts,
basementsandgaragesshouldbetreatedasexternal
runs and consideration should be given to using a
CondenseSure siphon..
Good practice
▶ The following guidance indicates the good practices
that must be maintained for the Installation and
Maintenance of a product.
0010012746-002
2
1
3
0010012767-002
75mm
min.
75mm
min.
6
6
1
1

Pre-Installation
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01)16
Condensate pump
figure 13
Where direct connection to “gravity discharge” is not physically
possible, or where very long internal runs would be required to reach a
suitable discharge point, condensate should be removed using a
proprietary condensate pump, of a specification recommended by the
boiler or condensate pump manufacturer.
• The pump outlet should discharge to a suitable “gravity discharge”
outlet.
– The condensate then flows, by gravity, through the 22mm plastic
pipe to the condensate discharge point.
Fig. 13 Condensate pump disposal
4.5.4 External connections
External disposal considerations
If no other discharge method is possible then the use of an externally run
condensate drainage pipe terminating at a suitable foul water discharge
point, or purpose-built soak away, may be considered. If this method is
chosen then the following measures should be adopted:
▶ The external run be kept as short as possible and ideally should not
exceed three metres.
Additional precaution against freezing must be taken if the external
pipe run does exceed three metres.
▶ The pipe should be run internally as far as possible before going
externally and the pipe diameter should be increased to a minimum
internal diameter (ID) of 30mm before it passes through the wall to
the exterior.
▶ The hole through the wall for the condensate pipe should be sleeved
and be sealed to the building fabric on the internal and external face
using a suitable building material.
▶ The external pipe should take the shortest and least exposed route to
the discharge point, and should "fall" as steeply as possible away
from the boiler, with no horizontal runs in which condensate might
stand.
▶ The use of fittings, elbows etc. should be kept to a minimum and any
internal “burrs” on cut pipe work should be removed so that the
internal pipe section is as smooth as possible.
▶ All external pipe drainage will be improved if the end is cut at 45° as
opposed to a straight cut.
▶ In situations where there are likely to be extremes of temperature or
exposure, the use of a proprietary trace-heating system for external
pipework, incorporating an external frost thermostat, should be
considered. All other guidance above and the instructions for the
trace heating system, should be closely followed.
▶ As well as trace heating, other methods for protecting pipework that
are run externally should be considered to prevent freezing during
prolonged cold periods.
– Insulation materials can be used, these should be of class “O”
grade with an outer coating that is weather proof and have a UV
resistant finish. A minimum of 19mm thick insulation is
recommended for 32mm external pipes.
– The use of a drain cover (such as those to prevent leaf blockage)
may offer further protection from wind chill.
Additional protection for transition through a wall
The external pipework can be insulated to help prevent freezing during
prolonged cold periods.
• Where insulation is required, the entire run of external pipework [5]
should be insulated with a recess in the external face allowing better
insulation protection coverage [4] as it transitions to the outside of
the building.
• The hole through the wall must be sealed to the building fabric on the
internal [1] and external [3] face using a suitable building material,
(use a 40mm sleeve [2] to pass the condensate pipework through
and then seal the internal and external faces).
Fig. 14 Additional protection for transition through a walll
[1] Internal face sealed (32mm pipe sealed to sleeve)
[2] 40mm sleeve
[3] External face sealed (32mm pipe sealed to sleeve)
[4] Insulation recessed into the wall
[5] Condensate discharge pipe
NOTICE: Septic tanks
Untreated condensate must not be allowed into septic
tanks.
▶ Connection to systems which drain into a septic tank
should be avoided due to the risk of affecting
anaerobic bacteria.
NOTICE: Rainwater or external drain disposal
Untreated condensate must not be allowed to flow into
streams or rivers
▶ A rainwater down pipe or an external drain shall only
be used for condensate disposal if the down pipe or
external drain is connected to a combined foul and
rainwater system
▶ Refer to BS 6798 for more information
NOTICE: Grey water systems
Contamination of recovered water
▶ Condensate disposal shall not be allowed into a grey
water recovery system that is intended for re-use
NOTICE: Freezing conditions
Frozen condensate will block the condensate drain pipe
and stop the appliance from running.
▶ Pipe work length should be kept to a minimum and
the route as vertical as possible.
NOTICE: Condensate waste disposal
▶ Care should be taken when siting a soak-away to
avoid causing damage to existing services and
building footings.
0010023656-002
Min.
Max.
1
8C
7
0010026770-002
1
2
3
4
5

Pre-Installation
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01) 17
Rain water down pipe with external air break
figure 15
• Refer to the following example to dispose of condensate to a rain
water down pipe.
• An air break or rain water hopper must be utilised, between the
appliance condensate outlet andthedrainpipe, outsidethe property,
to avoid flooding of the appliance should the downpipe become
obstructed.
Fig. 15 Disposal into a rainwater down pipe
[1] Condensate discharge from appliance
[8] Pipework transition
[9] External disposal considerations (page 16)
[10] External rain water pipe to foul water
[11] External air break
[12] Air gap
[13] Strap-on fitting
[14] 43mm 90° male/female bend
[20] Rain water hopper
[21] Increase pipe size
Open drain or gully with external air break
figure 16
Where the pipe terminates over an open drain or gully and there is a risk
of ground flooding, then the additional requirement below is
recommended:
• An air break should be installed in the external pipework as shown to
avoid an airlock during ground flooding/adverse weather conditions
which could prevent the condensate from discharging.
Fig. 16 Disposal to open drain or gully with air break
[1] Condensate discharge from appliance
[8] Pipework transition
[9] Additional protection for transition through a wall (page 16)
[11] External air break
[21] Increase pipe size
Condensate soak away considerations
Before deciding to use a purpose-made soak away the history of the
locality and the ability of the surrounding area to disperse the
condensate should be taken into account, e.g. areas prone to flooding
and ground with a high clay content can result in poor drainage with an
increased risk of water logging or freezing causing the condensate pipe
to become obstructed by water or ice and the boiler to shut down.
Although it is possible to increase the size of the soak away and the area
with limestone chippings in clay soil areas, if the clay content is high and
prevents effective dispersal of the condensate then a soak away may not
be a suitable means of condensate disposal and an alternative method
should be used.
Condensate soak away with external air break
• Refer to following example to dispose of condensate to a soak away.
• The condensate soak away must be sited at least 500mm away from
building footings.
• The condensate drainage pipe may be run above or below the ground
to the soak away. The following example shows drainage pipe run
above ground.
• The soak away must use a minimum of a 100mm Ø plastic tube with
two rows of three 12mm holes on 25mm centres and 50mm from the
bottom of the tube. The holes must face away from the house.
• The tube must be surrounded by at least 100mm of limestone
chippings to a depth of 400mm.
• An air break must be installed in the external pipework as shown to
avoid an airlock during ground flooding/adverse weather conditions
which could prevent the condensate from discharging.
Good practice
▶ The following guidance indicates the good practices
that must be maintained for the Installation and
Maintenance of a product.
1
0010012784-003
1
8
8
10
11
20
12
10
12
13
21
14
9
9
Minimum hole size for the condensate soak away must
be 400mm deep by Ø 300mm.
25mm min.
1
0010012786-003
8
11
21
21
9

Pre-Installation
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01)18
Fig. 17 Disposal to soak away
[1] Condensate discharge from appliance
[8] Pipework transition
[9] Additional protection for transition through a wall (page 16)
[11] External air break
[15] 100mm minimum O plastic pipe
[16] Drainage holes
[17] Limestone chippings
[18] Bottom of sealed tube
[19] Increase size of soak away size and the area with limestone
chippings if in clay soil area.Not recommended for high clay soil
areas.
[21] Increase pipe size
Appliances with condensate pump, CondenseSure accessory or
have trace heating fitted.
The need to insulate the pipe work through the wall is not normally
required for appliances with a condensate pump or CondenseSure/
trace heating fitted for external runs under three metres.
Trace heating fitted:
• Check with trace heating manufactures instructions for additional
requirements.
Condensate pump or CondenseSure fitted to the appliance
• External pipe work exceeding three metres in length or installation
with increased risk of freezing due to environmental factors:
– Additional protection of insulating the entire run of the
condensate pipework [2] should be carried out. The pipe should
be insulated externally using suitable waterproof and weather
resistant insulation.
– The hole through the wall must be sealed to the building fabric on
the internal [1] and external [3] face using a suitable building
material.
Fig. 18 To a soak-away
4.6 Pressure relief pipework
• The pressure relief discharge pipe [1] should be at least 15 mm
diameter copper pipe and run downwards away from the boiler and
discharge away from any electrical or other hazard, preferably to an
external drain or soak away.
• Pipe [3] should be finished with a partial bend, near the outlet to face
the external wall (as shown) to help prevent freezing.
Fig. 19 Pressure relief pipe work
[1, 3] PRV discharge pipe
[2] Outside wall
[4] External drain
4.7 Boiler locations and clearances
This boiler is only suitable for installing internally within a property at a
suitable location onto a fixed rigid surface of the same size as the boiler
and capable of supporting the boiler weight.
The boiler must be installed on a flat level surface to ensure condensate
does not enter the primary heat exchanger.
The boiler is not suitable for external installation unless a suitable
enclosure is provided.
Roof space installations must fully conform to BS 5410 part 1: roof
space installations.
Open flue model (CF)
In order to ensure clean and efficient combustion an adequate supply of
air must be delivered to the combustion chamber.
Minimum standard
▶ The following guidance indicates the minimum
standardsthat must bemaintainedforthe Installation
and Maintenance of a product.
500mm min.
25mm min.
400mm min.
15
16
0010012788-002
1
15
11
21
16
21
181719
9
8
0010036808-001
1
2
3
4
1
2
3
4
2
3
4
1
2
6720646608-123.1Wo

Pre-Installation
Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01) 19
To provide sufficient air a suitable inlet must be provided into the room
or space in which the boiler is situated.
An air brick or other form of continuous air supply may have to be built
into the installation in order to ensure an adequate supply of air.
If the appliance is to be installed in a confined space or compartment two
air vents are required, one at high level and one at low level.
The minimum free area of each vent is shown in table 4 and depends
whether the air is taken from another room or from outside the building.
Where the air is taken from another room that room must contain an air
inlet as described above.
Room sealed flue (RS)
The appliance does not require a separate vent for combustion air.
Installation in cupboards or compartments require permanent vents for
cooling purposes, one at high level and one at low level, either direct to
outside air or to a room.
Both vents must pass to the same room or be on the same wall to the
outside air.
The minimum air vent free area is given in table 5.
Installation clearances
Figure 20 shows the minimum space recommended to install the boiler
only.
Fig. 20 Installation clearances
Service clearances
Figure 21 shows the minimum space required to carry out an annual
service.
* Remove the flue "knock-out" panel sections if this clearance is less than
75mm.
The appliance is suitable for an under worktop installation providing that
the worktop above the boiler (min 10mm clearance) is removable for
maintenance and repair and the front of the boiler is not enclosed.
Fig. 21 Service clearances
Maintenance clearances
Figure 22 shows the clearances required for maintenance.
* Remove the flue "knock-out" panel sections if this clearance is less than
75mm.
Fig. 22 Maintenance and repair clearances
Minimum air vent area (cm3) for appliances installed in
compartments
Compartments
Follow the requirements of BS 5410 and note:
Minimum clearances must be maintained.
An access door is required to install, service and maintain the boiler and
any ancillary equipment.
If fitting the boiler into an airing cupboard use a non-combustible
material (if perforated, maximum hole sizes of 13mm) to separate the
boiler from the airing space.
Venting compartments
There must be sufficient clearance around the appliance to allow proper
circulation of ventilation air. The clearances required for installation and
servicing will normally be adequate for ventilation.
Ventilation must be provided for boilers fitted into compartments as
described in BS 5410.
Combustion air must not be taken from a room or internal space
containing a bath or shower and must not communicate with a protected
area such as a hall, stairway, landing, corridor, lobby, shaft etc.
Air vents must allow access for clean free air and must be sited to comply
with the flue terminal position requirements.
Air duct runs must not exceed 3 m.
Low level air vents must be less than 450mm from the floor.
A warning label must be added to the vents with a statement to the
effect: “Do not block this vent. Do not use for storage”.
Output 12/18 18/25 25/32
Size cm299 138 165
300m
m
1
00m
m
720m
m
1
00m
m
12
0
0
m
m
1
15
5
m
m
600mm
6720813344-16.1Wo
10mm
5m
m
*
530m
m
5
mm
*
12
0
0
m
m
865mm
600
m
m
6720813344-17.1Wo
Model
Internal ventilation External ventilation
High level Low level High level Low level
12/18 198 297 99 198
18/25 275 413 138 275
25/32 330 495 165 330
Table 4 Conventional flue
Model
Internal ventilation External ventilation
High level Low level High level Low level
12/18 198 198 99 99
18/25 275 275 138 138
25/32 330 330 165 165
Table 5 Room sealed flue
300m
m
5mm
*
530m
m
5mm
*
12
0
0
m
m
1
15
5
m
m
600mm
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Greenstar Heatslave II 2022 + 6 721 843 978 (2022/01)20
Rooms containing a bath or shower
Refer to figure 23, the boiler must not be installed in zones 1 or 2.
The boiler can be installed outside the shaded areas.
Fig. 23 Bathroom zones
[2*] Without end wall, zone 2 must extend 600mm from the bath
[*] 600mm radius from the bath or shower
4.8 Flue gas system considerations
Room air dependant operation
The boiler primarily operates as a “room air sealed” unit, however the
boiler can be operated as a “room air dependant” unit, if required.
Provide sufficient boiler room ventilation when operating the appliance
room air dependent.
▶ Do not obstruct or block any ventilation openings.
▶ Ventilation openings must always be kept clear.
4.8.1 Combustion air quality
To avoid corrosion, combustion air must be free from aggressive
substances (e.g. hydrogen halide, chlorines and fluorine).
4.8.2 Flue terminal positions
• Flue terminals must be positioned to avoid combustion products
entering into buildings.
• The flue must be fitted and terminated in accordance with the
recommendations of the latest version of BS 5410:1.
• The flue must not cause an obstruction.
• Discharge from the flue outlet must not cause a nuisance or dispute.
• Flue gases have a tendency to plume and in certain weather
conditions a white plume of condensation will be discharged from the
flue outlet which could be regarded as a nuisance, for example, near
security lighting.
• There should be no restriction preventing the clearance of
combustion products from the terminal.
• The air inlet/outlet duct and the terminal of the boiler must not be
closer than 25mm to any combustible material. Detailed
recommendations on protection of combustible materials are given
in the latest version of BS 5410:1.
• Where a vertical flue terminates in an area that is enclosed on 3 sides,
the flue must be no more than 1,000mm below the lowest roof line.
You must ensure that all clearances are maintained and that products
of combustion disperse safely from the area.
• Dimensions from a flue terminal to a fanned air inlet to be determined
by the ventilation equipment manufacturer.
• A protective stainless steel terminal guard, must be fitted if the
terminal is 2 metres or less, above a surface where people have
access.
• See “Contact Information” on the back cover for flue guard
information.
WARNING: Conventional flues
▶ Conventional flue boilers must not be installed in a
bathroom
WARNING: Electric shock
▶ Any switch or appliance using mains electricity must
not within reach of a person using the bath or shower.
In all cases the installation must be in accordance with
the latest amendments in the latest edition of the IET
wiring regulations (BS7671)
6720646608-124.4Wo
2*
*Radius 600mm
1
212
2
1
600mm
600mm 600mm
2250mm
2250mm
2*
*
*
*
CAUTION: Non accessible flue systems:
▶ Where a flue system is not going to be accessible,
provision must be made for service and inspection.
▶ Flue gas system must comply with local standards
and regulations.
NOTICE: Damage to appliance from contaminated
combustion air and contaminated air in the vicinity of
the appliance!
▶ Never operate the boiler in a dusty chemically
aggressive environment i.e. spray painting, hair
dressing and farming facilities.
▶ Never operate the boiler in places where using or
storing trichlorethane, hydrogen halide and other
aggressive chemical substances. These substances
can be contained in spray cans, various glues,
primers, paints and cleaning substances.
In this case, the appliance must be connected in a
room sealed configuration.
All measurements are the minimum clearances required