Greenstar i Greenstar i Greenstar i
Greenstar i Greenstar i Greenstar i
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Greenstar i overview

Our Greenstar i combi boiler is the replacement for the well-established award-winning Greenstar i Junior, which has been installed in over 1 million homes across the UK.

Perfect for small to medium sized homes with one bathroom, the boilers' new features have been designed based on installer feedback. These boilers now include increased outputs, higher hot water flow rates of up to 12.3 litres/min, a user friendly control panel and a larger condensate siphon that eliminates the risk of condensate freezing*.

Earn 10 points with these products on the Greenstar Reward Programme

Features & Benefits

Wall mounting jig providing pre-plumbing and rear piping as standard
Low lift weight
Single panel front for ease of removal
Central heating flow and hot water temperatures can be adjusted using simple up/down buttons
Plug & play optional Worcester controls available
Fan can be removed with just one screw and the expansion tank is now inside the boiler
Large siphon inside - eliminates risk of condensate pipe freezing*
Clear text description for quick boiler diagnostics
Simple weather compensation option
Simple boiler controls with clear information display
Commissioning information for easier completion of the Benchmark checklist
Homeowner service reminder
Achieves an A+ ErP package efficiency rating for heating when installed with a Wave smart internet connected control
Scan and register the boiler using our FREE online registration app

Technical Details

Greenstar 25i Greenstar 30i
Part number 7 733 600 012 7 733 600 005
ErP Efficiency Rating
ErP Data Sheet ErP Data Sheet ErP Data Sheet
Solar Compatible
Wave Compatible
Control Options
Dimensions (mm) height x width x depth 710 x 400 x 330 710 x 400 x 330
Clearances (mm) above, sides, below and front 30, 5, 200, 600 30, 5, 200, 600
Maximum horizontal flue (mm) 4600 4600
Maximum vertical flue (mm) 6400 6400
Ingress protection rating X4D X4D
Wall mounting jig supplied
Central heating output (kW) 24 24
Max DHW output (kW) 25 30
Hot water flow rate (litres per minute) 10.2 @ 35°c ∆T 12.3 @ 35°c ∆T
Minimum inlet pressure (bar) 1.3 2
NOx emissions (mg/kWh) 49 (39 with a code plug) 49 (39 with a code plug)
Lift weight (kg) 31.7 31.7

*The Condensesure Siphon has been proven to be effective at preventing frozen condensate at -15°C for a sustained period of 48 hours. 32mm pipework must be used and should not exceed 3 metres in length

Frequently Asked Questions

Can I use artificially softened water in the heating circuit with my boiler?
Can Worcester products be used with underfloor heating?
What ventilation do I need?
Do you recommend treatment of the central heating water?
How does part L of the Building Regulations affect my boiler installation?
What is ErP?
What is Energy Labelling?
How will ErP affect me and my business?
How will ErP benefit me and my business?
Under ErP, what about systems that contain different products?
How do controls affect ErP?
As an installer, am I required to print the efficiency label? Or am I required to make a label and send it out?
Can you advise where to find and learn more on how to calculate and provide an ErP label?
What if I install a system with a programmer or other non-Worcester components? Will I still be able to use the Worcester ErP online tool?
Why is it necessary when we already have an appliance label and a home Energy Performance Certificate both of which are based on the well understood A-G scale?
Which programmers are compatible with my gas boiler?
Can I put flue elbows straight on top of the boiler?
Do I need a standoff kit to pipe up the back of your boilers?
Why is the boiler blowing fuses?
Why is the pump running constantly on a Greenstar CDi boiler?
Where can I find the FD (serial) number on a Greenstar boiler?
Can I fit your controls to an external oil boiler?
Can I run boiler flues outside?
Does an external condensate pipe have to be insulated?
Can I use third party controls with your boilers?
Why is the controller on a combi boiler twin channel?
Do I remove the link wire in the boiler when fitting a Worcester control?
Which connector block do I use on a Greenstar boiler when wiring a Wave smart internet connected controller?
Can I put flue elbows straight on top of the boiler?
Why is the pump running constantly on a Greenstar CDi boiler?
Can I use artificially softened water in the heating circuit with my boiler?
Find answer to more frequently asked questions

Related Accessories

Boiler Accessories Part number
Keyless Filling Link 7 716 192 610
Earth bonding strip 7 716 192 686
Heat exchanger cleaning kit 7 733 600 091
Filling link 7 716 192 281
Vertical Pre-piping Assembly Kits 7 716 192 713
Flashing Kits Part number
Pitched roof flashing kit (100mm & 125mm dia) 7 716 191 091
Flat roof flashing kit (100mm & 125mm dia.) 7 716 191 090
Flue Part number
Long telescopic flue kit (100mm dia.) 7 716 191 171
Horizontal flue kit (125mm dia.) 7 719 003 702
Support bracket kit (100mm dia.) 7 716 191 177
Support bracket (125mm dia.) 7 716 191 179
High level horizontal telescopic 60/100mm flue kit 7 733 600 048
Support bracket 6 pack (100mm dia.) 7 716 191 178
60/100mm (x2) 45º bends 7 716 191 085
Vertical BF kit (100mm) 7 719 002 430
90º bend (100mm dia.) 7 716 191 084
1000mm extension kit (100mm dia.) 7 716 191 083
Short flue extension, 220mm (100mm dia) 7 716 191 133
2m flue extension (100mm dia.) 7 716 191 172
High level horizontal flue adaptor (100mm dia) 7 719 002 432
Standard telescopic horizontal flue kit (100mm dia) 7 716 191 082
Plume Part number
Plume management kit (60mm dia) 7 716 191 086

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