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Baxi expansion vessel 8L 5114691

Ucp

Baxi expansion vessel 8L 5114691

An 8-litre pressurised expansion vessel with an integrated pressure relief valve, fitted across Baxi Duo-tec, Platinum Combi, Megaflo System and selected Main and Potterton boilers.

At a glance

  • Also known as 2081144
  • Have a Gas Safe registered engineer fit and re-pressurise the system
Manufacturer part no.
JJJ005662620
Showing prices

£67.68

£56.40 ex. VAT · VAT at 20%

Available to order · 7 working days
Available to order · 7 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 5114691 is an 8-litre expansion vessel made by Baxi, fitted inside the boiler casing to absorb the increase in water volume as the central heating system heats up. It ships with an integrated pressure relief valve (248056) and carries GC number H289-989.

Signs this part needs replacing

  • Boiler pressure gauge creeps up or drops repeatedly between top-ups
  • Pressure relief valve drips or discharges water
  • Boiler locks out on a pressure fault
  • Banging or knocking noises from the pipework as the system heats up

Before you order

  • Match part number 5114691 printed on the existing vessel before ordering
  • Isolate and depressurise the system before removal
  • Have a Gas Safe registered engineer fit and re-pressurise the system

Not sure which part?

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