Worcester Greenstar 4000 21KW System Boiler

Worcester Greenstar 4000 21kW System Boiler

The Worcester Greenstar 4000 21kW System Boiler is a reliable and efficient choice for medium to large homes, especially those that use a stored hot water cylinder. Designed to deliver consistent heating performance, this model balances energy efficiency with everyday practicality. Its compact, lightweight build makes installation straightforward, even in tighter spaces. The boiler comes with a built-in pump and expansion vessel, helping installers achieve a tidy and efficient setup. Homeowners can also enhance comfort and control through a wide range of optional heating controls, including modern smart thermostats for improved efficiency.

Key Features

Compact, space-saving design Built-in pump and expansion vessel Optional plug-in diverter valve Compatible with a wide range of optional heating controls Ideal for medium to large homes using a hot water cylinder

Technical Information

Manufacturer: Worcester Bosch Model: 4000 MPN: 7733600383 SKU: 79146 GTIN: 4057749856722 Product Type: Gas System Boiler Performance: CH Output: 21kW CH Output (BTU): 71,000 ErP Heating Rating: A Rated for Heating Dimensions: Height: 724mm Width: 400mm Depth: 310mm Weight: Gross Weight inc Packaging: 40kg Warranty: 7 Years (Subject to manufacturer T&Cs)

FAQs

Is the 21kW output suitable for my home?

The 21kW model is ideal for **medium to large properties**, particularly those with several radiators and a stored hot water cylinder.

Do I need a hot water tank with this boiler?

Yes — as a **system boiler**, it works with a hot water cylinder but does not require a loft-installed cold water tank.

Can I add smart controls to this boiler?

Absolutely. The Greenstar 4000 range supports a variety of **optional and smart heating controls**, including wireless and app-based options for better efficiency and convenience.

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