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Andrews Expansion Vessel C782

Andrews

Andrews Expansion Vessel C782

25 litre expansion vessel for Andrews water heaters and unvented hot water systems.

At a glance

  • Also known as 1820840
Manufacturer part no.
C782
Showing prices

£242.66

£202.22 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 Andrews C782 is a 25 litre expansion vessel used on Andrews water heaters and unvented hot water systems. It absorbs the expansion of heated water within a sealed system, limiting pressure rise and protecting the cylinder, valves and pipework from excessive stress. The vessel is charged with air on one side of an internal diaphragm, which compresses as system water expands.

Signs this part needs replacing

  • System pressure rises sharply when the water heats up and falls again once it cools
  • Water discharges from the pressure relief valve during heating cycles
  • The vessel feels heavy or sounds full of water when tapped
  • Water weeps from the air valve (Schrader valve) on the vessel
  • Pressure is lost repeatedly and requires frequent topping up

Before you order

  • Confirm your appliance model against the fitment list above
  • Check the existing vessel is a 25 litre unit and that the connection arrangement matches
  • Verify the system pressure and vessel charge pressure before fitting
  • Inspect the mounting position and available clearance for the replacement vessel

Not sure which part?

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