Baxi Boiler Expansion Vessel 7L 7683801

Product Overview

The Baxi Boiler Expansion Vessel 7L (Part Number: 7683801) is a replacement expansion vessel assembly designed for use within selected Baxi heating systems.

The expansion vessel is an important component of a sealed heating system. It accommodates the increase in water volume that occurs as the heating system heats up, helping to control pressure changes and maintain stable system operation.

The 7683801 is a 7-litre expansion vessel assembly and is supplied as a complete vessel assembly rather than a repair kit. Baxi documentation also identifies 7683801 as an expansion vessel spare part.

ℹ️ Product Condition Options:

This part may be available in New or Refurbished condition. Please check the available options from the dropdown menu.

Technical Insight & Common Failure Symptoms

An expansion vessel contains an internal diaphragm separating the heating system water from a pressurised air or gas chamber. As the system water heats and expands, the vessel provides space for this expansion, helping to prevent excessive increases in system pressure.

Over time, an expansion vessel may lose its charge or the internal diaphragm may deteriorate, reducing its ability to manage pressure correctly.

Typical symptoms associated with an expansion vessel requiring replacement or servicing include:

• Boiler pressure rising significantly when the heating is operating
• Frequent pressure loss from the heating system
• Frequent need to repressurise the boiler
• Pressure relief valve discharging water
• Large fluctuations in system pressure
• Expansion vessel losing its ability to absorb thermal expansion

A correctly sized and functioning expansion vessel helps maintain stable pressure and reliable operation of the sealed heating system.

Technical Specifications

• Manufacturer: Baxi
• Manufacturer Part Number (MPN): 7683801
• Type: Expansion Vessel Assembly
• Capacity: 7 Litres
• Pack Quantity: 1

The 7-litre capacity and part number 7683801 are confirmed by Baxi parts documentation and UK boiler-spares suppliers.

Compatibility

This part is designed for selected models within the Baxi range and is also used under the same manufacturer part number in selected Main and Potterton applications.

Please strictly verify the manufacturer part number 7683801 against your boiler's technical manual, exploded parts diagram, or existing expansion vessel before ordering to guarantee correct fitment.

Safety Advice

Expansion vessels form part of a sealed heating system and operate under pressure. Installation, replacement, pressure adjustment, and boiler servicing should only be carried out by a suitably qualified heating engineer in accordance with the manufacturer's instructions and applicable UK safety regulations.