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Worcester Bosch By-Pass Pipe Assembly 87161064370

Worcester Bosch

Worcester Bosch By-Pass Pipe Assembly 87161064370

Worcester Bosch by-pass pipe assembly (87161064370) for Greenstar i and i ErP system boilers, forming part of the internal pipework circuit.

At a glance

  • Part type: Hoses and pipes
  • Also known as 1014909
  • This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Manufacturer part no.
87161064370
GC number
H10-089
Showing prices

£35.45

£29.54 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 by-pass pipe assembly is a Worcester Bosch internal pipework component used in Greenstar system and combi appliances. It sits within the boiler's hydraulic circuit and provides the by-pass route that keeps a minimum flow through the heat exchanger when system demand falls away. The assembly is supplied as a complete pipe section with its formed bends and connections already in place, so it can be swapped as a single item rather than rebuilt from individual fittings.

Signs this part needs replacing

  • Water weeping or staining around the pipe joints or compression connections inside the casing
  • Visible corrosion, pitting or heavy scale build-up on the pipe surface
  • Boiler short-cycling or overheating where the by-pass route is restricted or blocked
  • Kettling or rushing noises from the pipework when the boiler modulates down
  • Flow-related fault codes appearing after the heating load drops off

Before you order

  • Check the GC number on the appliance data badge against the compatibility list before ordering, as several Greenstar variants use different internal pipework.
  • Confirm the part number 87161064370 or the alternative number 1014909 matches the item being replaced.
  • Inspect the joint seals and washers on removal and replace them if they are compressed or perished.
  • 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.