Worcester Bosch Flow Regulator 13 Litre 87186884090

The Worcester Bosch 13 litre flow regulator is a water-side control component used in the hydraulic circuit of Greenstar condensing boilers. It governs the rate at which water passes through the appliance, keeping flow within the design range so that heat transfer and domestic hot water delivery stay consistent. This is the olive green variant, identified by Worcester Bosch part number 87186884090.

• Domestic hot water temperature that fluctuates or drifts away from the set point during draw-off.
• Reduced flow rate at the tap or shower outlet compared with the appliance's normal performance.
• Scale, debris or discoloured deposits visible around the regulator body or its seating.
• Water weeping or tracking from the regulator area inside the boiler casing.
• Boiler cycling or locking out where flow through the hydraulic circuit is restricted.

• Check the appliance GC number and serial plate against the compatibility list, as the same boiler range can use different hydraulic components across build variants.
• Confirm the part number on the existing component matches 87186884090 before ordering, and note the alternative number 1031251 where it appears on older documentation.
• Inspect the seals and olives in the regulator housing while access is available, as these are commonly disturbed during removal and refitting.
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.