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Ferroli Expansion Vessel 39821700

Ferroli

Ferroli Expansion Vessel 39821700

A 9 litre expansion vessel for Ferroli Optimax HE 31S and 38C gas boilers, part number 39821700.

At a glance

  • Also known as 1210994
Manufacturer part no.
39821700
Showing prices

£256.09

£213.41 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 Ferroli 39821700 is a 9 litre expansion vessel used in Ferroli Optimax HE gas boilers. It absorbs the change in water volume as the heating circuit heats and cools, keeping system pressure within the range the appliance expects. It is a serviceable component within the boiler's hydraulic circuit.

Signs this part needs replacing

  • Boiler pressure rises sharply while the heating is running and falls back when cold
  • The pressure relief valve discharges water during heating cycles
  • System pressure drops repeatedly and needs frequent topping up
  • The vessel feels heavy or full of water when checked at the valve
  • The pressure gauge needle swings widely as the boiler cycles

Before you order

  • Confirm the boiler model and GC number against the list above
  • Check the existing vessel's part number and capacity against the manufacturer's parts list for your appliance
  • Verify the system cold fill pressure and vessel charge pressure before fitting
  • Check access to the vessel mounting point on your appliance

Not sure which part?

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