BOSS 25L Expansion Vessel 3 Bar for Sealed Heating & Chilled Water Systems
Original price was: £125.98£104.98.£58.13£48.44Current price is: £58.13£48.44. £58.13£48.44 inc VAT Incl. VATExcl. VAT
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Description
BOSS Expansion Vessel 25L (3 Bar) – Sealed Heating & Chilled Water Systems
The BOSS Expansion Vessel 25L (3 Bar) is a high-performance sealed expansion vessel designed for closed-loop heating systems and chilled water applications. Engineered to accommodate thermal expansion and contraction caused by temperature fluctuations, it helps maintain stable system pressure, protect heating and cooling equipment, and improve overall system efficiency.
Manufactured from a high-strength steel shell and featuring a fixed butyl rubber diaphragm, the vessel effectively separates air and water to deliver reliable pressure management and long service life. The integrated nitrogen-charged air valve with protective cap ensures dependable operation in residential and commercial heating systems.
Key Features
- 25 litre expansion vessel capacity
- Maximum working pressure: 3 bar
- Pre-charge pressure: 1.5 bar
- Fixed butyl rubber diaphragm
- High-strength steel vessel construction
- Nitrogen air valve with protective cap
- Suitable for sealed heating systems
- Suitable for chilled water systems
- Long service life and easy installation
- Compatible with water and glycol mixtures up to 50%
- CE Approved
- Manufactured in accordance with PED 97/23/EC and BS 4814:1990
Technical Specification
| Specification | Value |
|---|---|
| Capacity | 25 Litres |
| Maximum Working Pressure | 3 Bar |
| Pre-Charge Pressure | 1.5 Bar |
| Connection Size | ¾” BSP Male |
| Diameter | 358 mm |
| Height | 356 mm |
| Weight | 7.3 kg |
| Part Number | 19711063 |
Applications
The BOSS 25L Expansion Vessel is suitable for:
- Sealed central heating systems
- Chilled water systems
- HVAC installations
- Residential heating systems
- Commercial heating systems
- Closed-loop heating and cooling circuits
- Plant room applications
Compatible Mounting Bracket
For a secure and professional installation, the BOSS 18L Expansion Vessel can be paired with the BOSS Expansion Vessel Mounting Bracket (Part No. 19713001). The bracket is designed to provide stable wall mounting, simplify installation, and reduce stress on connecting pipework.
Installation Guidance
For optimum performance, the expansion vessel should be installed on the coldest section of the system, typically the return pipework to the boiler, heat pump, or heat exchanger. Correct installation helps maintain accurate pressure control, protects the diaphragm, and maximises service life.
Order Information
BOSS Expansion Vessel 25L (3 Bar)
Part Code: 19711063
Compatible Mounting Bracket: 19713001
Contact LoCO2 Heat for pricing, availability, and technical support.
Helpful Expansion Vessel Guides
Want to get the best performance from your expansion vessel? Our expert guides explain everything you need to know, from choosing the correct vessel size to setting and maintaining the right system pressure.
• Expansion Vessel Sizing: A Comprehensive Guide – Learn how to calculate the correct vessel size for your heating or chilled water system and avoid common sizing mistakes.
• Expansion Vessel Pressure Guide – Understand pre-charge pressure, system pressure requirements, troubleshooting tips, and how to maintain efficient system operation.
Read our guides before installation to ensure your system is correctly sized, pressurised, and protected.
Additional information
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The documents and links below provide installation guidance and product information to support the use of this product.
Supporting guidance on sizing and pressure setup:
Expansion vessel sizing guide
Expansion vessel pressure setting guide




