Zilmet Cal-Pro Vertical Expansion Vessel - 4 Bar. - 18Ltr Zilmet CAL‑PRO expansion vessels are designed for sealed heating systems to absorb thermal expansion as water temperature increases.

Built for sealed heating (EN 12828) and chilled-water systems, Flexcon Premium Expansion Vessels stabilise system pressure by absorbing thermal expansion so plant runs safely and efficiently.

A new TPO (thermoplastic polyolefin) diaphragm on 1235 Ltrs models delivers high flexibility and extremely low permeability, helping the pre-charge hold for longer. Lighter construction cuts material use and transport emissions; packaging is FSC-certified to reduce CO₂ impact.

• Sustainable design lighter TPO membrane uses up to 50% less material
• Long service life 15-year warranty
• Low permeability pre-charge pressure maintained for longer
• Heating & cooling suitable for LPHW and CHW installations

Vessels comply with EN 13831 and the Pressure Equipment Directive 2014/68/EU. Red epoxy powder coating (RAL 3002). Flexcon Premium 3580 are supplied with feet and a mounting kit.

Built for sealed heating (EN 12828) and chilled-water systems, Flexcon Premium Expansion Vessels stabilise system pressure by absorbing thermal expansion so plant runs safely and efficiently.

A new TPO (thermoplastic polyolefin) diaphragm on 1235 Ltrs models delivers high flexibility and extremely low permeability, helping the pre-charge hold for longer. Lighter construction cuts material use and transport emissions; packaging is FSC-certified to reduce CO₂ impact.

• Sustainable design lighter TPO membrane uses up to 50% less material
• Long service life 15-year warranty
• Low permeability pre-charge pressure maintained for longer
• Heating & cooling suitable for LPHW and CHW installations

Vessels comply with EN 13831 and the Pressure Equipment Directive 2014/68/EU. Red epoxy powder coating (RAL 3002). Flexcon Premium 3580 are supplied with feet and a mounting kit.

Built for sealed potable hot and chilled water systems in domestic and commercial settings, these Potable Water Expansion Vessels stabilise pressure by absorbing thermal expansion for safe, reliable operation.

A nitrogen pre-charge helps retain set pressure longer, while a single threaded steel connection with plastic insert provides a durable, non-flow-through design. Suitable for central heating, cooling and tap water applications (not for solar collector circuits).

• Nitrogen gas filling for longer pre-charge retention
• Single threaded steel connection with plastic insert (no flow-through)
• Potable use supports domestic hot/chilled water
• Heating & cooling compatible for sealed systems

Designed for long service life with broad operating limits and glycol tolerance for demanding installations.

The HeatWave Vessel - Inline - 18Ltr is a Pressure Vessel item.

The HeatWave™ series hydronic expansion tanks provide quality protection for closed loop hydronic heating systems from excessive pressure due to thermal expansion.

Easy to install and featuring an incorporated hex nut connection, HeatWave™ tanks feature an air chamber sealed with a brass air valve and O-ring sealed air cap.  developed to be supported by either system piping, wall-mounted bracket (inline models) or be freestanding (vertical model with base), the HeatWave™ has a maximum working temperature of 99° C / 210° F .

The operating pressure of this is 6 bar.

• Diaphragm design
• Patented Stainless Steel (vertical models) or chromed steel (inline models) water connection

• Two-part polyurethane, epoxy primed paint finish
• Leak-free, O-ring sealed air valve cap
• Maintenance Free

Includes & Benefits

The PressureWave Vessel - Inline - 18Ltr is a Pressure Vessel item.

• Booster systems
• Well systems
• epoxy primed paint finish
• Leak-free, O-ring sealed air valve cap

The Refix HW 25 expansion vessel is designed for domestic water systems that are not used in DIN 1988 compliant drinking water installations.

Purpose-built for solar thermal circuits, the Flexcon Solar 8/2.5 [8Bar] expansion vessel supports sealed systems in line with EN 12828, keeping pressure stable in high-temperature applications.

A preformed butyl rolling diaphragm with extremely low permeability helps retain pre-charge, while a nitrogen fill limits corrosion and pressure loss. The clench ring clamps the diaphragm evenly to prevent damage, and a ribbed profile avoids sticking for instant inflow. An uncoated connection thread aids watertight installation; the steel vessel is finished in a gleaming epoxy-powder coat and factory tested.

• Solar-ready expansion vessel for sealed systems
• Butyl rolling diaphragm with very low permeability
• Nitrogen pre-charge for longer pressure stability
• Clench ring construction for a robust, uniform seal

For 880 Ltrs models: both halves are coated before assembly to protect the clamp ring, and the nitrogen valve is countersunk and covered. Continuous medium temperature range −10 to 110 C.

Purpose-built for solar thermal circuits, the Flexcon Solar 8/2.5 [8Bar] expansion vessel supports sealed systems in line with EN 12828, keeping pressure stable in high-temperature applications.

A preformed butyl rolling diaphragm with extremely low permeability helps retain pre-charge, while a nitrogen fill limits corrosion and pressure loss. The clench ring clamps the diaphragm evenly to prevent damage, and a ribbed profile avoids sticking for instant inflow. An uncoated connection thread aids watertight installation; the steel vessel is finished in a gleaming epoxy-powder coat and factory tested.

• Solar-ready expansion vessel for sealed systems
• Butyl rolling diaphragm with very low permeability
• Nitrogen pre-charge for longer pressure stability
• Clench ring construction for a robust, uniform seal

For 880 Ltrs models: both halves are coated before assembly to protect the clamp ring, and the nitrogen valve is countersunk and covered. Continuous medium temperature range −10 to 110 C.

Mains Liquid Boosting Setup

The Mainsboost 350 litre vertical composite vessel with 22 mm connections is installed directly onto the incoming liquid supply and under mains pressure fills with water. When the chamber is full the pump reaches a state of pressure equilibrium. The Mainsboost system now has a volume of pressurised water ready for distribution throughout the property and where required can be supplied with multiple vessels options.

The 2 vessel Mainsboost 350 litre vertical composite system with 22 mm connections are installed directly onto the incoming water supply and under mains pressure fills with water. When the chamber is full the pump reaches a state of pressure equilibrium. The Mainsboost system now has a volume of pressurised water ready for distribution throughout the property.

The 3 vessel Mainsboost 350 litre vertical composite system with 22 mm connections are installed directly onto the incoming water supply and under mains pressure fills with water. When the chamber is full the pump reaches a state of pressure equilibrium. The Mainsboost system now has a volume of pressurised water ready for distribution throughout the property.

The ElbiAC25 GPM 25 Litre Accumulator Pressure Vessel - 25 Ltr - 10 bar. is a Pressure Vessel item. This product is manufactured by Elbi.

The accumulator vessel is a device that fitted into a pressurised water system will provide system water at a pre-set sustained pressure.

Its most common application is to supply systems in which the main supply pressure is too low and a pump is fitted to boost the pressure to an acceptable level.

As system demands take place the accumulator vessel will sustain system pressure by feeding additional water into the system at the required pressure.

This process will limit the number of times the pump needs to start (pump hunting) in order that system pressure remains at the optimal level.

The operating pressure of this is 10 bar.

The accumulator vessel is a device that fitted into a pressurised water system will provide system water at a pre-set sustained pressure. This product is manufactured by Elbi. Its most common application is to supply systems in which the main supply pressure is too low and a pump is fitted to boost the pressure to an acceptable level. As system demands take place the accumulator vessel will sustain system pressure by feeding additional water into the system at the required pressure. This process will limit the number of times the pump needs to start (pump hunting) in order that system pressure remains at the optimal level.

The Elbi AFV 24-16 24 Litre Vertical Accumulator Pressure Vessel - 25 Ltr - 16 bar. is a Pressure Vessel item.

The operating pressure of this is 16 bar.

The MikroPro Expansion Vessels range serves almost any LPHW or CHW system, with capacities from 8500 Ltrs. Models up to 25 Ltrs are wall-mounted, while 35 Ltrs and above are floor-standing. This comes with a wall mount bracket.

With an 18Ltr capacity with an operating pressure of 3 Bar., this is built for performance, reliability and compliance, MikroPro vessels are PED 97/23/EC compliant, rated to a maximum operating temperature of 70 C, and available with pressure ratings of 3 Bar (835 Ltrs) or 6 Bar (501000 Ltrs). Threaded connections and a durable powder-coated finish simplify installation and maintenance.

• Capacities: 8500 Ltrs
• Mounting: wall (≤25 Ltrs) or floor (≥35 Ltrs)
• Ratings: up to 70 C, 36 Bar (model dependent)
• Applications: heating and chilled water systems

A versatile, robust choice for commercial and large domestic systems requiring stable expansion capacity and long service life.

Built for sealed LPHW/CHW systems, this Airfix Expansion Vessel delivers reliable performance with a tidy, installer'friendly form.

For use in potable water, or fresh-water installations.

The Airfix D expansion vessels operate in such a way that the water flows right through and they are continuously flushed with fresh water from the mains.

This prevents tepid, stagnant water from collecting in the vessel in which bacterial growth could occur.

Therefore, users can be assured of high quality potable water.

Applying an Airfix D expansion vessel to a water heater prevents the opening of the safety group or safety valve each time the potable water is heated.

Engineered for day'to'day plantroom demands, it helps maintain stable operation, protects equipment, and simplifies maintenance.

• Reliable absorption of system expansion
• Factory pre-charge for quick commissioning
• Durable diaphragm construction

Pair with suitable isolation, safety devices and treatment to meet site requirements and best practice.