Worcester 4000 Combi Boiler Review December 12, 2021 Greenstar 4000 Combi review.The Greenstar 4000 is designed for small to medium-sized homes with one bathroom, it is a direct replacement for the Greenstar i range. It features a sleek new look, an easy-to-use full-colour text display and is very quiet too. The Greenstar 4000 has a range of power outputs to meet a variety of heating and hot water needs.Available in both natural gas and LPG.The 4000 comes in two Combi models - 25kW and 30kW with hot water flow rates up to 12.3 l/min.Guarantee Lengths Standard Guarantee - 7 YearsWith any Greenstar System Filter - 8 YearsWith any Greenstar System Filter + £150 (Non-WAI Excelerate members only) - 10 YearsThe 4000 range can run on a 20% hydrogen blend - so you can be confident it will run on gas for its lifetime.A wide power range helps to reduce gas consumption and lower energy billsThe innovative 'Quick Tap' water-saving function helps you reduce water wasteThe modern new design comes with an easy-to-use colour displayOperates extremely well in low water pressure areas, ensuring powerful and warm showersOne of the quietest combi boilers available, making it easy to live withFeatures wireless connectivity with the Bosch EasyControlInstantaneous hot water is always availableSuitable for small to medium homesAndrew Tyler Gas Safe Registered Engineer covering Crawley and Horsham.