The Worcester Greenstar 22mm System Filter (part number 7733600236) is Worcester Bosch's 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. At its centre sits a powerful internal magnet that captures black iron oxide and other magnetic debris, while a cyclonic filtration design separates out non-magnetic particles such as solder and flux debris as water circulates through the unit.
Fitted on 22mm central heating pipework, the filter is bi-directional, so system water can flow through it in either direction, and it can be installed above, below or away from the boiler wherever access allows. With a proven capacity to collect up to 300g of debris, it offers strong first-pass collection and retention, and is compatible with a wide range of gas and oil boilers as well as heat pumps - not only Worcester Bosch appliances.
22 mm
Pipe Size
Up to 300g
Debris Collection Capacity
Bi-Directional
Flow Orientation
Magnetic + Non-Magnetic
Filtration Type
Sealed / Open Vented
System Compatibility
Annual
Recommended Service Interval
Competent Person Required
The Greenstar System Filter must only be installed by a competent heating engineer. Before fitting, drain the central heating system or isolate the feed and expansion tank and release system pressure. If in any doubt, consult a qualified heating engineer.
Contains a Powerful Magnet
This filter contains a strong internal magnet which can be harmful to pacemaker wearers. Installers and anyone servicing the unit should be aware of this before handling the filter body.
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 protection, Worcester Bosch recommends fitting it on the primary heating return, before the boiler and after the last radiator on a vertical run of pipework, with adequate access left for future servicing. On a system boiler with an internal 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 installing the Greenstar System Filter. Even a newly installed system can show visible magnetite within one to two days of commissioning, so fitting a filter from the outset helps protect the boiler and system components from the earliest stages of operation.
Powerful Central Magnet
A strong internal magnet positioned at the centre of the filter collects magnetite and other metallic debris quickly, helping to protect the heat exchanger, pump and valves.
High First-Pass Debris Capture
The filter's size and design slow the system water as it circulates, giving greater capture of debris on the first pass and improved retention compared with smaller inline filters.
Large 300g Debris Capacity
A proven collection capacity of up to 300g of debris gives strong long-term protection between services, even on systems with a higher contamination load.
Bi-Directional Installation
Bi-directional flow means the filter can be fitted with system water flowing in either direction, allowing installation above, below, or away from the boiler.
Simple Chemical Dosing
A built-in one-way 'quick dose' air vent lets installers add system chemicals and inhibitor directly at the filter without draining the system down first.
Straightforward Servicing
Supplied with dedicated body and cap spanners for the homeowner to keep, making future servicing of the filter simple without specialist tools.
General
Manufacturer Part Number (MPN)
7733600236
Pipe Size
22 mm
Filtration Type
Magnetic and non-magnetic (cyclonic design)
Debris Collection Capacity
Up to 300 g
Flow Direction
Bi-directional
System Compatibility
Sealed and open vented central heating systems; compatible with gas and oil boilers and heat pumps
Dimensions
Diameter
139 mm
Height
145 mm
Pipe Section Removed for Installation
70 mm
Included in the Box
Contents
Filter body, copper tails and fittings (22mm), tool for body, tool for cap, installation and servicing instructions
Servicing
Recommended Service Interval
Annually, alongside the main boiler service
Servicing Tasks
Isolate valves, release pressure via air vent, remove base, clean magnetic sheath, reassemble and re-tighten
Chemical Dosing
Via built-in 'quick dose' one-way air vent, compatible with standard chemical adaptors
Safety
Magnetic Field Warning
Contains a powerful magnet - can be harmful to pacemaker wearers
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 is the difference between this filter and the Greenstar Mini System Filter?
This is the standard Greenstar System Filter (7733600236), with a larger canister body, soldered copper elbow connections and a proven 300g debris capacity. The Mini System Filter is a more compact, compression-fitted alternative aimed at tighter installation spaces.
How much debris can this filter hold before it needs servicing?
The filter has a proven collection capacity of up to 300g of debris, giving strong protection between services when combined with an annual service alongside the main boiler service.
Can this filter be fitted to boilers other than Worcester Bosch?
Yes. While it shares its name with Worcester Bosch's boiler range, the Greenstar System Filter is designed to be compatible with a wide range of gas and oil boilers, as well as heat pumps, not only Worcester Bosch appliances.
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. Visible magnetite can appear within one to two days of a new system being commissioned, so fitting the filter early is recommended.
How is the filter serviced?
The filter is isolated using its valves, the internal pressure is released via the air vent, and the base is removed using the two spanners supplied to clean the magnetic sheath. These spanners should be left with the homeowner for future servicing.
Is it safe to install near a pacemaker?
The filter contains a powerful internal magnet which carries a warning that it can be harmful to pacemaker wearers. Installers and anyone servicing the unit should take this into account when handling it.
BTU & WATT Calculator
Room Dimensions
Room Type
Living Room
Bedroom
Kitchen
Bathroom
Conservatory
Hallway
Glazing Type
Single Glazed
Double Glazed
Triple Glazed
External Walls
0 Wall
1 Wall
2 Walls
3 Walls
4 Walls
Insulation Level
Poor
Average
Good (New Build)
Required Heating
0
Watts
0
BTUs
Documentation
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