The Worcester Greenstar 22mm Mini System Filter (part number 7733600266) is Worcester Bosch's own magnetic and non-magnetic central heating filter, designed to protect a boiler's heat exchanger, pump and valves from the damaging effects of contaminated system water. It combines a powerful internal magnet with a cyclonic trap to capture black iron oxide sludge alongside other non-magnetic debris circulating in the heating system.
Fitted on 22mm central heating pipework, the filter is bi-directional, so it can be installed with water flowing either top-to-bottom or bottom-to-top, and it suits both sealed and open vented systems. A range of installer-focused improvements - including an over-tightening prevention feature, isolation valve position indicators, and a detachable body for straightforward powerflushing - make it quicker to fit and service than earlier Worcester filter designs.
22 mm
Pipe Size
Bi-Directional
Flow Orientation
Magnetic + Non-Magnetic
Filtration Type
Sealed / Open Vented
System Compatibility
24 Months
Guarantee
Annual
Recommended Service Interval
Competent Person Required
The Greenstar System Filter must only be installed by a competent heating engineer. Before fitting, isolate the electrical supply to the heating system and drain the central heating circuit. If in any doubt, consult a qualified heating engineer.
Correct Positioning Matters
The filter can be installed almost anywhere in a heating system except between the boiler and the feed-and-expansion pipes on an open vented system. For best effectiveness, fit it on the primary heating return, before the boiler and after the last radiator on a vertical run, and ensure sufficient access is left for future servicing. On a system boiler fitted with a diverter valve, the filter should be positioned on the heating return rather than the cylinder return.
Flush the System First
Worcester Bosch recommends flushing the heating system and adding a suitable inhibitor in accordance with BS 7593 before fitting the Greenstar System Filter. On existing systems already showing signs of magnetite contamination, a chemical gravity flush, power flush, or MagnaCleanse® flush is recommended prior to installation to maximise the filter's effectiveness.
Stronger Magnet, Better Capture
A powerful internal magnet combined with a cyclonic trap removes black iron oxide sludge and other debris before it reaches the boiler's heat exchanger, pump and valves.
Over-Tightening Prevention
An over-tightening prevention feature on the isolation valves helps protect the fittings from installer error during fitting and servicing.
Clear Isolation Valve Indicators
Colour-coded isolation valve indicators make it easy to confirm at a glance whether the filter is open or closed for servicing.
Bi-Directional Installation
Bi-directional flow means the filter can be fitted with system water flowing in either direction, giving installers flexibility over pipework layout.
Simple Powerflushing & Servicing
A detachable body with a bottom drainage point makes it straightforward to service the filter and carry out a powerflush without removing it from the system.
One-Way Inhibitor Valve
A one-way valve allows system chemicals and inhibitor to be added directly at the filter without needing to drain the system down first.
General
Manufacturer Part Number (MPN)
7733600266
Pipe Size
22 mm
Filtration Type
Magnetic and non-magnetic (cyclonic trap)
Flow Direction
Bi-directional
System Compatibility
Sealed and open vented central heating systems
Dimensions
Height
209 mm
Width
198 mm
Depth
110 mm
Pipe Section Removed for Installation
150 mm
Included in the Box
Contents
Filter body, two isolating valves (A & B), valve C-clips, lid tool, pipe cutting template, installation and servicing instructions, guarantee card, 'System filter fitted' label
Servicing
Recommended Service Interval
Annually, alongside the main boiler service
Servicing Tasks
Isolate valves, drain filter, remove and rinse sleeve and trap, top up inhibitor, re-vent system
Compatible Inhibitors
Adey, Fernox and Sentinel system water treatment products
Guarantee
Standard Guarantee
24 months from date of installation, subject to terms and conditions
Extended Boiler Guarantee
Fitting a Greenstar System Filter can extend eligible Worcester Bosch boiler guarantees from 8 to 10 years
EAN Not Yet Confirmed
An EAN/barcode for this SKU could not be confirmed from an authoritative manufacturer or distributor source at the time of writing and has therefore been omitted rather than estimated.
What does the Greenstar Mini System Filter actually remove?
It captures black iron oxide sludge and other magnetic debris using its internal magnet, while non-magnetic particles are caught in traps at the top and bottom of the filter body, protecting the boiler's heat exchanger, pump and valves from contamination.
Can this filter be fitted to any boiler?
The filter is a generic central heating accessory suitable for sealed and open vented systems with 22mm return pipework, and is not restricted to a specific boiler model. It is however manufactured and recommended by Worcester Bosch for use with Worcester Bosch boilers.
Does fitting this filter extend my boiler's guarantee?
On eligible Worcester Bosch boilers, fitting a Greenstar System Filter can extend the standard guarantee from 8 to 10 years. Terms and conditions apply, and this does not apply when a System Filter Micro is fitted instead.
How often does the filter need servicing?
Worcester Bosch recommends the filter is serviced annually, at the same time as the main boiler service, by draining and rinsing the sleeve and trap and topping up the system inhibitor.
Do I need to flush my system before fitting this filter?
Yes. Worcester Bosch recommends flushing the system and adding a suitable inhibitor in line with BS 7593 before installation, with a power flush or MagnaCleanse® flush recommended if the system already shows signs of magnetite contamination.
BTU & WATT Calculator
Room Dimensions
Room Type
Living Room
Bedroom
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Bathroom
Conservatory
Hallway
Glazing Type
Single Glazed
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External Walls
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Insulation Level
Poor
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Good (New Build)
Required Heating
0
Watts
0
BTUs
Documentation
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