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Worcester Bosch Volumetric Water Governor 87174020020

Worcester Bosch

Worcester Bosch Volumetric Water Governor 87174020020

Worcester Bosch 87174020020 volumetric water governor for Greenstar combi and condensing boilers, regulating DHW flow through the hydraulic block.

At a glance

  • Part type: Diverter valves and hydraulics
  • Also known as 1020041
  • This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Manufacturer part no.
87174020020
GC number
E49-921
Showing prices

£40.63

£33.86 ex. VAT · VAT at 20%

Available to order · 3 working days
Available to order · 3 working days
Not certain it's the right part? The technical team verifies fitment before dispatch — no charge, and it stops a second trip.Call the technical teamSend a technical question

Same-day dispatch

Ordered by 4pm Mon–Fri, 10:30am Sat.

30-day returns

Unused, in original packaging.

What it is

The Worcester Bosch 87174020020 is a volumetric water governor used in the hydraulic section of Worcester Bosch and Worcester British Gas Greenstar boilers. It sits within the diverter valve and hydraulics assembly and controls the volume of water passing through the domestic hot water circuit, helping the boiler maintain a steady flow rate and temperature as draw-off demand changes. It is a serviceable hydraulic component and is not a gas-carrying part.

Signs this part needs replacing

  • Domestic hot water temperature swings between hot and lukewarm during a single draw-off.
  • Reduced hot water flow rate at the tap compared with previous performance.
  • The boiler cycles or struggles to hold a steady DHW setpoint, particularly at low flow rates.
  • Scale, sludge or debris visible around the governor or in the surrounding hydraulic block.
  • Weeping or dripping from the governor body or its seals.

Before you order

  • Check the GC number and appliance serial number against the compatibility list to confirm the governor suits your boiler.
  • Confirm the previous number DD97906500 or the alternative number 1020041 before ordering, as these identify the same component.
  • Inspect the seals and gaskets in the hydraulic block while the governor is removed, as these are commonly disturbed during the job.
  • This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.

Not sure which part?

Search by part number, product name or brand — our technical team confirms fitment before anything is dispatched.