Worcester Greenstar 12Ri Manual

Technical and Specification Information Greenstar CDi Classic
Regular Series
Greenstar Ri Series
Technical and Specification Information
Greenstar CDi Classic
Regular Series
Greenstar Ri Series
Greenstar regular gas-fired condensing
wall mounted boiler range

2
Worcester and you. Making a difference.
As part of the Bosch Group, Worcester
products are designed and manufactured to
provide customers with the highest levels of
quality and reliability which are synonymous
with the Bosch name throughout the world.
As part of Europe’s largest supplier of
heating products, Worcester, Bosch Group
has the UK-based resources and support
capability to offer you the value-added
solutions you deserve. Worcester employs
a nationwide network of Service Engineers
and technically trained Field Sales Managers
supported by an experienced technical
services team which is able to provide
comprehensive support and advice
from designing system layouts through
to installation.
Worcester is dedicated to providing energy
efficient gas- and oil-fired condensing
boilers, as well as an extensive range of
renewable technologies. All of our products
have been developed and introduced with
the aim of helping the UK to achieve the
Government’s efficiency targets.

3
“At Worcester we recognise the vital role you
play in the specification and installation of
energy efficient appliances in homes across
the UK. We will continue to invest in our
products, people, facilities and added value
services to ensure you have all you require
in order to deliver only the best solutions to
your customers’ requirements.”
Carl Arntzen,
Managing Director,
Bosch Thermotechnology Ltd.
Contents Page
The Greenstar condensing regular boiler range 4 - 5
Features of the Greenstar condensing regular
boiler range 6 - 7
Inside story – Greenstar Ri 8
Greenstar Ri regular technical data 9
Inside story – Greenstar CDi Classic Regular 10
Greenstar CDi Classic Regular technical data 11
Site preparations and guidance 12 - 15
Condensate pipework 16 - 17
The Worcester CondenseSure auxiliary siphon 18 - 19
Installation requirements 20 - 22
The Worcester Greenstar System Filter 23
Horizontal and vertical flue terminal positioning 24 - 25
Greenstar regular boiler range
horizontal fluing options 26 - 28
Greenstar regular boiler range
vertical fluing options 29 - 30
Plume management system options 31 - 35
Greenstar regular boiler range accessories 36 - 37
Greenfloor heating 38
Worcester training 39 - 41
After-sales 42
The reception and main entrance
at our Worcester headquarters

4
The Greenstar condensing
regular boiler range
The Greenstar regular range is part of a market leading
range of energy-saving condensing wall mounted
gas-fired boilers.
Floor standing regular boilers are also available from
Worcester in 30kW and 40kW outputs. For further
information see the FS CDi Regular Tech & Spec,
part no. 8 716 115 422.
Higher efficiency therefore highly cost effective
The Greenstar condensing regular boilers have an annual
efficiency (SEDBUK value) of over 90%, efficiently
producing heat for your heating and/or hot water system.
Non-condensing boilers achieve around 78% efficiency.
Therefore, compared with a non-condensing boiler,
Greenstar condensing regular boilers can cut heating and
hot water bills and are cheaper to run than an older boiler.
Hence, SEDBUK Band A ratings for all models in the
Greenstar condensing range.
Greenstar condensing regular boilers deliver this energy-
saving performance by recycling exhaust gases to extract
and re-use the latent heat – a highly efficient use of energy
which also significantly reduces carbon dioxide emissions
into the atmosphere.
To all these major benefits you can add yet more: renowned
Worcester quality and reliability; a range of outputs to
satisfy the heating demands of a range of households and
truly all-round value for money.
Greenstar 12Ri low NOx model
Worcester’s commitment to reduce emissions from gas-
fired condensing boilers now sees the 12Ri model achieve
NOx values <40mg/kWh. This enables the appliance to
achieve 3 credits under The Code for Sustainable Homes
whilst still achieving a SEDBUK A rating.

5
The Greenstar regular range at a glance
12Ri 15Ri 18Ri 24Ri 30CDi Classic
Regular
40CDi Classic
Regular
Output kW to
central heating (CH)
Min 4kW 5kW 6kW 8kW 7.7kW 9.4kW
Max 12kW 15kW 18kW 24kW 30kW 40.8kW
Primary temperature control 
Modulating control 
Natural gas 
LPG boiler 
Electronic ignition 

6
Features of the Greenstar condensing
regular boiler range
A condensing boiler is more efficient due to its ability to
extract more heat from the flue gases normally lost to the
environment through the flue system.
As the flue gases pass through the heat exchanger this
extra surface area can cool the flue gases to around 55°C
whereupon the latent heat within, which would normally be
lost to the atmosphere, is instead released and applied to
the system.
It is this ability to extract as much heat as possible from
the gas it burns that gives the Greenstar condensing regular
range an exceptionally high level of operating efficiency.
This higher efficiency is recognised within Section L of the
Building Regulations, subsequently achieving a higher SAP
or NHER rating.
Whenever a demand for DHW or CH is made, the boiler’s
electronic control system is energised and the burner
electronically ignites via a flame ionisation system.
The pre-mix burner automatically adjusts to the set level.
The flow temperature of the boiler is then maintained at the
customer setting by the fascia mounted variable control.
Should the system requirements reduce during operation
(TRVs closing down, etc.) and the flow temperature
exceed the customer setting then the burner will modulate
downwards to match the system demand level. Should the
flow temperature continue to rise then the burner will be
de-energised and the control system will go into an
anti-cycle mode and not allow the appliance to re-fire for
a set period.
Fluing options
The Greenstar regular range features 2 different sizes of
multi-directional RSF flue systems, 100mm or 125mm. The
flue can be run horizontally or vertically with additional 90º
or 45º in-line bends allowing changes of route or direction,
providing an extremely flexible and versatile fluing system
enabling the appliance to be sited virtually anywhere. More
details are shown on pages 26-30.
Greenstar Ri security features
• Security coding
• Non-removable wall screws.
Gas options
Greenstar regular boilers are manufactured in both natural
gas and Liquid Petroleum Gas (LPG) variants.
Greenstar CDi Classic Regular and Ri boilers
The Greenstar regular boilers are designed for connection
to a fully pumped heating and hot water system e.g. Y or
S plan. For this reason no plug-in controls are available
on Greenstar regular models. The advice of a controls
manufacturer should be sought.
• The Greenstar regular boilers are suitable for a wide range
of heating loads allowing extension to the heating system
without upgrading the boiler
• The Greenstar regular boilers are capable of operating on
both open vent and sealed primary water systems*
• Two or more Greenstar regular boilers can be linked
together to cater for commercial or industrial applications.
*Sealed systems require additional external components: expansion vessel and PRV (not supplied by Worcester)

7
*Where required – see installation booklet for further details. **Subject to terms and conditions.
1. Power ON/OFF switch
2. Burner ‘ON’ indicator LED
3. Service mode button
(Greenstar CDi Classic Regular only)
4. Inspection and advanced service mode button
(Greenstar CDi Classic Regular only)
5. Central heating temperature control selector
6. Mains ‘ON/OFF’ indicator with diagnostic sequence
7. Digital display (Greenstar CDi Classic Regular only)
8. Boiler reset button
9. ‘Eco’ mode (not operational on these boilers)
10. Holiday mode button
(Greenstar CDi Classic Regular only)
System controls
The Building Regulations Section L 2006 require a minimum
level of controls to be installed on all heating systems, both
on new build and refurbishment.
Generally, this would require:
• Room thermostat
• TRVs on all radiators, or at least those radiators in
sleeping areas if not already fitted. Do not fit TRVs in
the room in which the room thermostat is installed
• Time and temperature control for central heating and
domestic hot water
• Automatic by-pass.*
Further information is available in the Domestic Heating
Compliance Code.
Energy-saving & environmental features
• SEDBUK A Rated
• Low electrical consumption when the boiler is in
standby mode
• Aluminium-silicon heat exchanger delivers high efficiency
and reliability
• Electronic ignition
• Anti-cycle control
• Modulation control gives efficient use of energy
Time & labour-saving installation features
• All models available as natural gas and LPG
• Full range of Condensfit II™ flue options in both
60/100mm and 80/125mm diameters. 60/100mm includes
plume deflector as standard and plume management kit
available as an option
• Flow and return pipes supplied to allow pipes behind
installation
• Greenstar Ri weighs just 22.6kg making it the lightest
boiler in its class
End user comfort and convenience features
• 10 year guarantee on Worcester primary heat exchanger**
• Boiler protection plans available for both new and out of
warranty Worcester boilers
• Bosch renowned quality and reliability
• Built-in frost protection
• Optional anti-theft security fittings (Greenstar Ri only)
• Controls behind flap – aesthetically pleasing and
discourages children altering controls
(Greenstar CDi Classic Regular only)
• Compact dimensions of Greenstar Ri range make it ideal
for kitchen cabinet installation
Greenstar CDi Classic Regular fascia
1
2
3
4
56
7
8
9
10
Fascia features and control options
Greenstar Ri regular fascia
1 5
6
28

8
Inside story – Greenstar Ri
condensing regular boiler series
Fan pressure
test point
Air/gas manifold
Fan
Air/gas
adjustment screw
Gas valve
Inlet pressure
test point
Boiler power switch
Syphonic trap
Power and fault
indicator (blue)
Flame indicator
(green)
Cover for external
wiring connections
Flow connection
22mm compression
Drain point
Boiler thermostat
and reset knob
Return connection
22mm compression
Service access point
Flue overheat
thermostat
WB3 heat exchanger
Manual vent point
Sensor boiler flow
Over-heat thermostat
Silicon tube (use to vent
air from heat exchanger)
Removable top
case for cleaning
heat exchanger

9
Technical data
Model Greenstar 12Ri Greenstar 15Ri Greenstar 18Ri Greenstar 24Ri
Height (mm) 600 600 600 600
Width (mm) 390 390 390 390
Depth (mm) 270 270 270 270
Weight – dry (kg) 22.6 22.6 22.6 22.6
2005 SEDBUK value – natural gas 90.1% / A rated 90.1% / A rated 90.1% / A rated 90.2% / A rated
2005 SEDBUK value – LPG 91.4% / A rated 91.4% / A rated 91.4% / A rated 92.0% / A rated
2009 SEDBUK value – natural gas 88.8% 88.8% 88.8% 89.2%
2009 SEDBUK value – LPG 89.8% 89.8% 89.8% 90.2%
Heating flow / return connections 22mm compression 22mm compression 22mm compression 22mm compression
Gas connection 22mm compression 22mm compression 22mm compression 22mm compression
Primary water content (litres) 1.1 1.1 1.1 1.1
Max. flow temperature (ºC) 82 82 82 82
Output to central heating
kW 4 - 12 5 - 15 6 - 18 8 - 24
(Btu/h) (13,648 - 40,944) (17,060 - 51,180) (20,472 - 61,416) (27,296 - 82,000)
Max. vertical flue (mm) (100mm dia.)
inc. terminal 6,400 6,400 6,400 6,400
Max. vertical flue (mm) (125mm dia.)
inc. terminal 15,000 15,000 15,000 15,000
Max. horizontal flue (mm) (100mm dia.) 4,600 4,600 4,600 4,600
Max. horizontal flue (mm) (125mm dia.) 13,000 13,000 13,000 13,000
NOx classification (mg/kWh) 39 60 84 66
NOx class 5545
Noise output level (dB(A)) 39 42.7 43.7 41

Inside story – Greenstar CDi Classic
Regular condensing boiler series
10
Auto air vent
Air/gas
adjustment screw
Condensate syphon
Gas valve
Down firing
low NOx burner
Aluminium/
silicon WB5
heat exchanger
Pre-mix fan
Drain point
Digital displayOn/off
button
Central heating
temperature control

11
Technical data
Model Greenstar 30CDi Classic Regular Greenstar 40CDi Classic Regular
Height (mm) 760 (max) 760 (max)
Width (mm) 440 440
Depth (mm) 360 (max) 360 (max)
Weight – dry (kg) 39.5 39.5
2005 SEDBUK value – natural gas 90.3% / A rated 90.2% / A rated
2005 SEDBUK value – LPG 92.3% / A rated 92.0% / A rated
2009 SEDBUK value – natural gas 89.5% 89.1%
2009 SEDBUK value – LPG 90.5% 90.2%
Heating flow / return connections 22mm compression 22mm compression
Condensate connection 22mm plastic pipe 22mm plastic pipe
Gas connection 22mm compression 22mm compression
Output to central heating
kW 7.7 - 30 9.4 - 40.8
(Btu/h) (26,272 - 102,360) (32,073 - 139,210)
Wall mounting jig  
Fault diagnostic display  
Flow and return pipes supplied to allow pipes behind installation  
Max. vertical flue (mm) (100mm dia.) inc. terminal 9,400 4,900
Max. vertical flue (mm) (125mm dia.) inc. terminal 18,500 16,000
Max. horizontal flue (mm) (100mm dia.) 7,900 6,000
Max. horizontal flue (mm) (125mm dia.) 18,500 12,500
NOx classification (mg/kWh) 33.3 32.2
NOx class 5 5

12
Site preparations and guidance
The Greenstar regular boilers are designed for connection
to a traditional heating and hot water system. The major
benefits are:
• The boiler is compatible with S and Y plan systems
• The boiler comes supplied with a wall mounting bracket
and a plastic bottom panel.
Greenstar regular boilers are exceptional for their number
of additional time saving installation features:
• Built-in frost sensor for boiler protection
• Built-in fault finding diagnostics
• Automatic gas pressure adjustment
• Highly versatile multi-directional fluing system
• Combined ignition and control board means
fewer connections
• A rigid 22mm compression gas connection eliminating
the need for pre-fabricating the gas pipe onto the
isolating valve
• The large output range capability of the appliances
• A syphonic condensate trap is pre-plumbed within
the boiler
• Pre-fabricated pipes allowing top exit from the boiler
Siting of appliance
General
The appliances are only suitable for installing internally
within a property at a suitable location onto a fixed, rigid
surface at least the same size as the appliance and capable
of supporting its weight.
No surface protection is required against heat transfer
from the boiler. However, if the appliance is to be fitted
in a timber frame building the guidelines laid down in
BS 5440:Part 1 and the CORGI publication “Gas
Installations in Timber Frame Buildings” should be
adhered to.
The appliances may be installed into an airing cupboard
if required. Use a non-combustible perforated material
(max. hole sizes of 13mm) to separate the boiler from the
airing space. See section “Compartment Installation” on
page 15.
Clearances
The minimum clearances shown below should be allowed
for installation and servicing. Compartment ventilation
would be required at these clearances.
960mm 450mm
+30mm
above elbow
5mm
5mm
200mm
25mm to
removable
door
600mm front
clearance
for service
Using 100mm
flue kit
– 1,112mm
Using 125mm
flue kit
– 1,152mm
Clearances for Greenstar CDi Classic Regular
870mm 400mm
+30mm
above elbow
5mm
5mm
200mm
25mm to
removable
door
600mm front
clearance
for service
Using 100mm
flue kit
– 980mm
Using 125mm
flue kit
– 1,010mm
Clearances for Greenstar Ri

13
Compartment installation
The appliance may be installed in any room, although
particular attention is drawn to the requirements of the
IEE regulations applicable and in Scotland the electrical
provisions with respect to installation in a room containing
a bath or shower.
1. The room in which the appliance is installed does not
require a purpose provided air vent.
2. If the appliance is installed in a cupboard or
compartment with dimensions that allow the following
minimum clearances, then no ventilation is required:
Greenstar CDi Classic Regular wall mounting jig
Wall preparation
The following diagrams show the wall mounting jigs which
enable a simple and straightforward method of attaching
the boiler to the wall surface.
The wall mounting jig for the Greenstar CDi Classic Regular
has additional optional fixing points and provides improved
engagement. After fixing the jig to the wall, the appliance
can be lifted onto the jig and the union connections
tightened. The pipework can be routed behind the boiler
without the need for an additional wall spacing frame.
Greenstar Ri boilers come complete with a wall mounting
bracket which enables a simple and straightforward method
of attaching the boiler to the wall surface. After fixing to the
wall, the flow, return and gas supply can be connected. The
boiler also features levelling screws which allow the alignment
to the wall to be adjusted in line with the wall finish. This is
particularly useful on uneven walls and tiled surfaces.
Greenstar Ri pipe re-orientation
The flow and return pipework can be orientated to exit out
of the bottom of the appliance if desired. The pipework tails
are simply removed from the compression fittings and are
directed downwards behind the chassis.
+30mm
above elbow
200mm*
200mm*
200mm
100mm to
removable door
600mm front
clearance for
service
+30mm
above elbow
5mm
5mm
200mm
25mm to
removable door
600mm front
clearance for
service
Greenstar Ri
*This can be reduced to 50mm for one side, provided that the total side
clearances add up to 400mm or more.
+30mm
above elbow
200mm*
200mm*
200mm
100mm to
removable door
600mm front
clearance for
service
+30mm
above elbow
5mm
5mm
200mm
25mm to
removable door
600mm front
clearance for
service
Greenstar CDi Classic Regular
Ventilation free compartment installation – minimum clearances
Greenstar Ri wall mounting bracket
Compartment installation
Position of
appliance
Min. unventilated clearance
(to removable door)
Greenstar Ri Greenstar CDi
Classic Regular
In front 100mm 20mm
Below 200mm 200mm
Right side 200mm* 5mm
Left side 200mm* 5mm
Above flue elbow 30mm 30mm

14
Pipework connections and casing dimensions
(When fitted to wall frame) Depth to wall
Greenstar Ri
A
C
B
Greenstar Ri
45 65 220
BA
C
Greenstar CDi Classic Regular
A BC
A
C
B
Greenstar CDi Classic Regular
Cabinet dimensions (mm)
Greenstar Ri
A600
B390
C270
Greenstar CDi Classic Regular
A750*
B440
C360
*760mm to top of casing front.
Pipework connections
ACH flow 22mm
BCH return 22mm
CGas inlet 22mm

15
600mm
600mm
2,250mm
600mm
600mm radius
750mm
750mm
2,250mm
2,250mm
1
22
1
1
12
22,250mm
600mm
600mm
2,250mm
600mm
600mm radius
750mm
750mm
2,250mm
2,250mm
1
22
1
1
12
22,250mm
Boiler location & clearances
Bathrooms
IMPORTANT:
Any switch or appliance control using mains electricity must
not be within reach of a person using the bath or shower.
Electrical switches, fused spurs and socket outlets must
not be situated in the bathroom.
A boiler fitted with a non-mechanical timer or with no timer
can be installed in zone 2 or outside the shaded area.
A boiler with a mechanical timer or RF mechanical timer
with a room thermostat must only installed outside the
shaded area.
Additional Residual Current Device (RCD) protection may
be required.
Refer to the latest IEE wiring regulations.

Important points to consider when siting a condensate
drainage pipe:
• Where a new or replacement boiler is being installed,
access to an internal “gravity discharge” point should
be one of the factors considered in determining
boiler location
• The condensate pipe must be a minimum of 22mm dia.
plastic pipe
• The condensate pipework must fall at least 52mm per
metre towards the outlet and should take the shortest
practicable route
• Ensure there are no blockages in the pipe run.
Internal connections
In order to minimise risk of freezing during prolonged cold
spells, the following methods of installing a 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. (see fig. 1)
Alternatively, if the first option is not possible, an internal
kitchen, bathroom or washing machine waste pipe etc. can
be used. (see fig. 2)
Condensate pump
Where “gravity discharge” to an internal termination 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 pipe should discharge to a suitable internal
foul water discharge point such as an internal soil and vent
stack, internal kitchen, bathroom or washing machine waste
pipe etc. A suitable permanent connection to the foul waste
pipe should be used. (see fig. 3)
Condensate pipework
100mm
75mm min.
Visable air break
at plug hole
Sink with
integrated
overflow
75mm sink
waste trap
Condensate
pump
Soil
& vent
stack
22mm dia.
22mm
dia.
22mm dia.
Siphon
trap
Min. 450mm &
up to 3 storeys
Internal Options
75mm min.
Siphon
trap
Siphon
trap
Visable air break
at plug hole
Sink with
integrated
overflow
75mm sink
waste trap
Fig. 1 Disposal to soil vent stack
100mm
75mm min.
Visable air break
at plug hole
Sink with
integrated
overflow
75mm sink
waste trap
Condensate
pump
Soil
& vent
stack
22mm dia.
22mm
dia.
22mm dia.
Siphon
trap
Min. 450mm &
up to 3 storeys
Internal Options
75mm min.
Siphon
trap
Siphon
trap
Visable air break
at plug hole
Sink with
integrated
overflow
75mm sink
waste trap
Fig. 2 Disposal to a waste pipe
100mm
75mm min.
Visable air break
at plug hole
Sink with
integrated
overflow
75mm sink
waste trap
Condensate
pump
Soil
& vent
stack
22mm dia.
22mm
dia.
22mm dia.
Siphon
trap
Min. 450mm &
up to 3 storeys
Internal Options
75mm min.
Siphon
trap
Siphon
trap
Visable air break
at plug hole
Sink with
integrated
overflow
75mm sink
waste trap
Fig. 3 Condensate pump disposal
16

Pipework
transition
500mm min.
25mm min.
400mm
min.
Siphon
trap
Bottom of sealed tube
Limestone chippings
100mm
dia. min.
plastic
pipe
25mm min.
External
rain water
pipe into
foul water
External
air break
Air gap
25mm min.
Insulate
& increase
pipe size
Condensate
pump
External Options
100mm dia.
Siphon
trap
Siphon
trap
Siphon
trap
Pipework
transition
Insulate
& increase
pipe size
Pipework
transition
Pipework
transition
Insulate
& increase
pipe size
68mm dia. PVCu
strap on fitting
Condensate
pump
Insulate
& increase
pipe size
Drainage
holes
100mm
dia. min.
plastic pipe
25mm
25mm
50mm
25mm
300mm
Drainage
holes
12mm dia.
Fig. 4 Disposal into a rainwater down pipe
Pipework
transition
500mm min.
25mm min.
400mm
min.
Siphon
trap
Bottom of sealed tube
Limestone chippings
100mm
dia. min.
plastic
pipe
25mm min.
External
rain water
pipe into
foul water
External
air break
Air gap
25mm min.
Insulate
& increase
pipe size
Condensate
pump
External Options
100mm dia.
Siphon
trap
Siphon
trap
Siphon
trap
Pipework
transition
Insulate
& increase
pipe size
Pipework
transition
Pipework
transition
Insulate
& increase
pipe size
68mm dia. PVCu
strap on fitting
Condensate
pump
Insulate
& increase
pipe size
Drainage
holes
100mm
dia. min.
plastic pipe
25mm
25mm
50mm
25mm
300mm
Drainage
holes
12mm dia.
Fig. 5 External disposal
Pipework
transition
500mm min.
25mm min.
400mm
min.
Siphon
trap
Bottom of sealed tube
Limestone chippings
100mm
dia. min.
plastic
pipe
25mm min.
External
rain water
pipe into
foul water
External
air break
Air gap
25mm min.
Insulate
& increase
pipe size
Condensate
pump
External Options
100mm dia.
Siphon
trap
Siphon
trap
Siphon
trap
Pipework
transition
Insulate
& increase
pipe size
Pipework
transition
Pipework
transition
Insulate
& increase
pipe size
68mm dia. PVCu
strap on fitting
Condensate
pump
Insulate
& increase
pipe size
Drainage
holes
100mm
dia. min.
plastic pipe
25mm
25mm
50mm
25mm
300mm
Drainage
holes
12mm dia.
Fig. 6 Soak away
For full technical information on pipe size, insulation
and different condensate pipework methods please
see Installation, Commissioning and Servicing
Instruction Manual.
Condensate soak away (see fig. 6)
• The condensate drainage pipe may be run above or below
the ground to the soak away
• The examples shown run above ground
• The soak away must use a 100mm dia. 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
• Minimum hole size for the condensate soak away must be
400mm deep by 300mm dia.
In situations where there are likely to be extremes of
temperature or exposure, the use of a proprietary trace
heating system for external pipework (that incorporates
an external frost thermostat) should be considered. If
such a system is used, the requirement to use 32mm pipe
does not apply, however all other guidance above, and the
instructions for the trace heating system, should be
closely followed.
Unheated internal areas
Internal pipe runs in unheated areas such as lofts,
basements and garages should be treated as external runs,
with consideration given to using a CondenseSure siphon.
External connections
Freezing conditions
• When the position of the boiler prevents internal
routing, we recommend installing a Worcester
CondenseSure siphon to minimise the risk of freezing
• Pipework length should be kept to a minimum and the
route as vertical as possible
• Weather-proofing insulation must be sized when not
using a CondenseSure siphon.
Condensate waste
• Care should be taken when siting a soak away to avoid
obstructing existing services.
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 (fig. 4), or purpose-
designed soak away (fig. 5), may be considered. Please see
installation and servicing instructions for more details.
In addition to the condensate discharge options illustrated
on these pages and in the Installation, Commissioning
and Servicing Instruction Manual, the new Worcester
CondenseSure auxiliary siphon provides an innovative
alternative for the prevention of freezing for externally run
discharge condensate (see over for details).
17

18
With climate change and extreme weather variations
becoming increasingly common, and very cold winters with
temperatures as low as -20°C being experienced, practices
such as externally run condensate discharge pipework are
now being questioned.
The CondenseSure auxiliary siphon has been designed to
allow a more flexible approach to boiler siting.
Tested to extreme temperatures
The CondenseSure has been extensively tested under
simulated extreme weather conditions and proved its
effectiveness in preventing frozen condensate at -15ºC
for a sustained period of 48 hours.
CondenseSure principle of operation
Within most condensing boilers there is an internal siphon
which holds around 100ml of condensate before being
released down the condensate discharge pipe. A typical
high efficiency condensing boiler will generate up to 2
litres of condensate an hour (dependant on output and
temperature) and this will result in the in-built siphon
discharging approximately every 3 minutes. With this
frequency of discharge it is unlikely that the condensate
pipework is ever empty of condensate, consequently
increasing the potential for freezing of the pipework in
prolonged sub-zero temperatures.
The CondenseSure siphon connects to the boiler
condensate discharge outlet and collects the condensate
into a larger volume before releasing it into the
discharge pipe.
With this expanded siphonic operation, the discharge from
the CondenseSure is every 15 to 20 minutes, resulting in:
• Increased velocity and flow rate
• With only 3 to 4 siphonic actions per hour,
the condensate pipework is empty for longer
• Significantly decreased or even eliminated
freezing potential.
A universal fitting for new and existing installations
Although developed specifically for Worcester Greenstar
gas- and oil-fired boilers, the Worcester CondenseSure
has the added advantage of being able to be fitted to
any make of condensing boiler for both new and retrofit
installations. The CondenseSure can provide a simple
solution which eliminates the need for re-siting both the
new boiler and the system pipework when replacing an
existing non-condensing appliance. The CondenseSure can
easily be fitted to existing installations to provide peace of
mind in extreme weather conditions.
The Worcester CondenseSure
auxiliary siphon NEW
The CondenseSure insulating jacket helps to retain the temperature
of the condensate.
Features Benefits
No power consumption
No electrical wiring
connection or supply needed,
meaning zero running costs
No moving parts No failure of components
Can be installed on new or
existing installations
Suitable for any gas- or
oil-fired condensing boilers
Can be attached to 22mm
heating flow pipework
Uses ‘free’ energy from the
pipe to heat the condensate
Under boiler or remote
installation Flexibility
No electrical connections No electrician needed
No pipe insulation needed Cost saving and aesthetically
pleasing

19
Fitting to a regular boilerEase of installation
The CondenseSure has been designed for ease of
installation in mind and is suitable for most boiler
applications. For maximum effectiveness it should
be installed immediately beneath the boiler where
it is clipped on to the boiler’s heating flow pipe and
connected to its siphonic trap. If this is not practical,
the CondenseSure can be wall-mounted away from the
boiler and connected to a 32mm condensate discharge
pipe. However, this will sacrifice the benefit of warming
the condensate prior to discharge and therefore slightly
reduce its performance.
Additional installation considerations include:
•
Keeping any external pipework as short as possible
•
Minimising the number of bends and connections
• Removal of burrs after cutting pipe
•
Removal of surplus solvent from the
interior of the pipe.
The CondenseSure has no working parts to breakdown,
does not use any energy and has no electrical connections,
so there is no Part P requirement.
1.
2.
3.
7
1
2
3
5
6
4
1. Foam backing with double-sided tape
2. Siphon mounting screws
3. Siphon body
4. Foam insert (used with regular or system boilers)
5. Foam cover
6. CH flow pipe
7. CH return pipe Greenstar Ri only
1
2
2
3
4
5
6 7
A typical installation using CondenseSure
External pipework
3000mm max.
CondenseSure 2.5º fall min.
32mm OD pipe
Siphon
trap
The CondenseSure
clips onto the
22mm heating
flow pipe using
the ‘free’ heat
to raise the
condensate
temperature.
Product info
Part number 7 716 192 746
The CondenseSure installation parameters
The CondenseSure will protect an externally run condensate
discharge pipe from freezing for 48 hours at -15°C providing
the following installation parameters are met:
• The externally run pipe length does not exceed 3 metres
• There is a fall on the discharge pipe of at least 2.5 degrees
• The discharge pipe diameter is not less than 32mm
in diameter.
Whilst it is not necessary to insulate the pipework it may
be a consideration if longer lengths or if lower external
temperatures are expected.

20
Installation requirements
Installation of the Greenstar regular boiler range must
be in accordance with the relevant requirements of the
Gas Safety (Installation Use) Regulations (as amended),
current IEE Wiring Regulations, local Building Regulations,
Building Standards (Scotland) regulations and bylaws of
the local Water company and Health and Safety Document
No. 635 (Electricity at Work Regulations 1989). It should be
in accordance with the relevant recommendations of the
following British Standards:
BS 6798; BS 5449; BS 5546:1; BS 5440:1; BS 5440:2;
BS 6891.
Gas Safety (Installation and Use) Regulations. All gas
appliances must be installed by a Gas Safe registered
person in accordance with the above regulations. Failure to
install appliances correctly could lead to prosecution.
The manufacturer’s notes must not be taken in any way as
overriding statutory regulations.
It is important with an aluminium heat exchanger that the
pH level of the water does not exceed 8. Levels in excess of
this could be detrimental to the heat exchanger.
The use of a suitable inhibitor will provide a resistance
to this. Contact Sentinel (Tel: [phone]) or
Fernox (Tel: [phone]) for further details.
Sealed primary systems
The appliance is fitted with a manual reset high limit
thermostat and is suitable for use with a sealed
primary system.
The system should be installed in compliance with the
requirements of BS 5449: Part1. The system must be fitted
with a spring loaded safety valve set to operate at 3bar
(45 psi) and the pipe connections made through the system
must be capable of sustaining a pressure of up to 3bar.
Manual air vents should be fitted at any high points in
the system.
The following is a list of major items which must be fitted
to the system:
1. Safety valve – 3bar
2. Pressure gauge – 0 - 4bar
3. Expansion vessel
4. Automatic air vent
System filling and make-up
To comply with the Water Authority requirements, the
system should be filled via a temporary hose connection
to the mains cold water supply, with a double check valve
assembly and test point fitted to the mains water side of a
temporary circuit.
Valves and joints
It is very important that all valves and joints are able to
sustain a working pressure of up to 3bar (45psi). Particular
care should be exercised when fitting radiator valves and
only those of high quality to BS 2767:10 should be used.
All other valves and fittings should comply with BS 1010.
Loss of water pressure from a sealed system will require
continuous recharging with fresh water and consequential
introduction of air. Air is highly corrosive and will
considerably reduce life expectancy of radiators,
pumps etc.
Plastic pipework
The use of plastic pipework is acceptable. However, some
plastics are permeable to oxygen and must be avoided.
Only pipework with a polymeric barrier should be used.
Please note that the first 600mm of pipework connected to
the boiler must be of copper or steel.
Typical fully pumped sealed system