Baxi Expansion Vessel - 8 Litre - 5114691
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Product Information
Full details
This 8-litre Baxi expansion vessel (part number 5114691) is designed for homeowners and heating engineers to maintain safe and consistent pressure within sealed heating systems. Its key benefit is protecting boilers and system components from damage caused by pressure fluctuations due to water expansion when heated. A potential caveat is that it requires professional installation to ensure correct integration into the heating system. This compact, flat expansion vessel absorbs excess pressure, ensuring system longevity and reliability, and comes supplied with a 3 Bar Pressure Relief Valve (PRV) for added safety.
All features
| Model Part Number | 5114691 |
|---|---|
| Brand | Unvented Components Europe |
Extended Product Information
FAQs
What is the purpose of an expansion vessel?
An expansion vessel absorbs the excess water volume created when a sealed heating system heats up. This prevents dangerous pressure build-up and protects system components.
Do I need to pre-charge the expansion vessel with air?
The vessel typically comes pre-charged. However, for optimal performance and after any system draining, it's recommended to check and adjust the air pressure (when the system is cold and drained) to match the system's cold-fill pressure.
How often should the expansion vessel be checked?
It's advisable to have the expansion vessel and system pressure checked annually by a qualified heating engineer as part of routine boiler maintenance. Monitor system pressure for any sudden changes between services.
Can I install this myself?
No, this component should only be installed by a qualified and competent heating engineer or plumber to ensure safe and correct operation within your central heating system.
What does the 3 Bar PRV do?
The 3 Bar Pressure Relief Valve is a safety device. If the system pressure exceeds 3 Bar (due to a faulty expansion vessel or other issues), the valve automatically opens to release water, preventing damage to the boiler and pipework.
How do I know if my expansion vessel needs replacing?
Signs include consistently dropping system pressure, the PRV frequently discharging water, or physical signs of corrosion/damage on the vessel. A heating engineer can diagnose these issues.
Is this vessel suitable for open-vented systems?
No, this expansion vessel is specifically designed for sealed (pressurised) central heating systems. Open-vented systems use a different pressure management method involving an open-to-atmosphere feed and expansion cistern.
Troubleshooting
System pressure is too high or fluctuating excessively.
The expansion vessel may have lost its air charge or be waterlogged. Check the vessel's air pressure (when the system is fully drained) and re-charge if necessary. Ensure the vessel is correctly sized for the system. The PRV may be activating if the vessel is faulty or undersized.
The Pressure Relief Valve (PRV) is constantly discharging water.
This indicates excessive system pressure. Check the expansion vessel for damage or loss of air charge. Ensure the vessel is correctly installed and appropriately sized. An internal leak within the heating system could also cause pressure build-up.
Low system pressure after installation or maintenance.
Ensure the heating system has been correctly refilled and vented. Check the expansion vessel connection for leaks. Verify the system is filled to the correct cold-fill pressure.
Corrosion or leaks at the vessel connection.
Isolate the system, drain it, and carefully remove the vessel. Clean the connection threads on both the vessel and the system. Re-apply appropriate thread sealant and re-install securely. Replace the vessel if corrosion is severe.
Pros and Cons
Pros
- Effectively manages pressure fluctuations in sealed systems.
- Protects expensive boiler and pipework components from damage.
- Includes a safety relief valve for enhanced protection.
- Compact design allows for installation in tight spaces.
- Built to Baxi's quality standards for reliability.
Cons
- Requires professional installation; not a DIY component.
- Specific to Baxi systems, though may be compatible with others.
- An 8-litre capacity might be insufficient for very large or complex systems.
- Requires periodic checks to ensure optimal performance.
Setup, Compatibility & Care
Setup:
- Isolate the System: Ensure the central heating system is fully drained and isolated from the water supply.
- Connect the Vessel: Securely connect the expansion vessel to the designated port on the heating system pipework or within the boiler. Ensure threads are clean and appropriate sealant is used if required.
- Install PRV: If not pre-fitted, ensure the 3 Bar Pressure Relief Valve is correctly installed in its designated location.
- Re-pressurize & Check: Refill the heating system to the recommended operating pressure (typically 1-1.5 Bar when cold) and check thoroughly for any leaks around the vessel connection.
- Test Operation: Once the system is operational, monitor pressure gauge readings during heating cycles to confirm the vessel is functioning correctly.
Compatibility:
- Primarily designed for Baxi boilers and heating systems.
- Ensure system pressure requirements match the vessel's capacity and the included 3 Bar PRV.
- Consult your boiler's installation manual or a qualified heating engineer for specific compatibility confirmation.
Care:
- Regular Checks: Periodically check the system's cold-fill pressure. If it drops consistently, the vessel may have lost its air charge or have a leak.
- Visual Inspection: Look for any signs of corrosion or damage to the vessel or its connections.
- PRV Test: It is good practice for a heating engineer to test the Pressure Relief Valve annually to ensure it operates correctly.