Worcester Bosch Flow Sensor Assembly 87161157540

Genuine Worcester OEM flow sensor for popular Greenstar and CDi models. The flow sensor (a flow switch with in-built sensor) sits in the boiler pipework and detects water movement to signal hot-water or heating demand to the control board.

• Manufacturer: Worcester Bosch
• Part type: Flow sensor / flow switch assembly
• MPN: 87161157540 (was 87161072230; superseded by 8716122562)
• GTIN / EAN: 4047416994567
• Kit contents: Typically supplied with clips & O-rings (check your pack)

Compatible boilers (examples)

Used across many Worcester appliances (variant/year dependent). Common fits include:

• Greenstar i / i System / i Junior 24i, 28i; 12i/15i/18i/24i System
• Greenstar i (ErP) 25i, 30i
• Greenstar Si 25Si, 30Si
• Greenstar CDi / CDi Classic 25/29/30/34/38/42 CDi
• British Gas badged 532i, 537i, 542i (CDi derivatives)

Always confirm against your boilers data plate/parts list for MPN 87161157540 (or its replacement 8716122562).

What this part does

Detects flow of water in the DHW/CH circuit and signals demand to the boiler PCB, enabling fast ignition and stable hot-water/heating operation.

When to replace

• No DHW ignition when taps open, or intermittent DHW
• Boiler fails to recognise demand / flow readings erratic
• Physical damage or failed sensor output

What’s in the box

• 1 Worcester flow sensor assembly 87161157540
• Clips & O-rings (if included by supplier)

Installation & safety

Must be installed by a qualified Gas Safe engineer. After fitting, check for leaks, verify correct DHW/CH activation and clear any stored fault codes.