ULTRA-PRO is appropriate for any modern installation and can be applied to any type of irrigation pump, centrifugal pump and booster sets.

The food grade membrane is replaceable. This product is manufactured by Zilmet. The membrane pressure tank's real volume is superior than that of a normal tank, therefore, it has a smaller footprint at equal water yield, minimum pump starts and is energy saving. The wide range available, the vertical and horizontal version, the galvanised and Stainless Steel connection flange makes Zilmet pressure tanks suitable for any application. The tank is factory tested and certified according to EU directive 97/23/EC. Maximum duration of the membrane is assured as the membrane itself cannot bend or rub against the plate as it is fixed above to the connection and below to the flange.

The tank's lifetime is practically unlimited as the membrane can be replaced.

The Zilmet Ultra-Pro Vertical Expansion Vessel - 10 bar. - 100Ltr is a Pressure Vessel item.

The operating pressure of this is 10 bar.

ULTRA-PRO is appropriate for any modern installation and can be applied to any type of irrigation pump, centrifugal pump and booster sets.

The food grade membrane is replaceable. This product is manufactured by Zilmet. The membrane pressure tank's real volume is superior than that of a normal tank, therefore, it has a smaller footprint at equal water yield, minimum pump starts and is energy saving. The wide range available, the vertical and horizontal version, the galvanised and Stainless Steel connection flange makes Zilmet pressure tanks suitable for any application. The tank is factory tested and certified according to EU directive 97/23/EC. Maximum duration of the membrane is assured as the membrane itself cannot bend or rub against the plate as it is fixed above to the connection and below to the flange.

The tank's lifetime is practically unlimited as the membrane can be replaced.

The Zilmet Ultra-Pro Horizontal Expansion Vessel - 10 bar. - 100Ltr is a Pressure Vessel item.

The operating pressure of this is 10 bar.

ULTRA-PRO is appropriate for any modern installation and can be applied to any type of irrigation pump, centrifugal pump and booster sets.

The food grade membrane is replaceable. This product is manufactured by Zilmet. The membrane pressure tank's real volume is superior than that of a normal tank, therefore, it has a smaller footprint at equal water yield, minimum pump starts and is energy saving. The wide range available, the vertical and horizontal version, the galvanised and Stainless Steel connection flange makes Zilmet pressure tanks suitable for any application. The tank is factory tested and certified according to EU directive 97/23/EC. Maximum duration of the membrane is assured as the membrane itself cannot bend or rub against the plate as it is fixed above to the connection and below to the flange.

The tank's lifetime is practically unlimited as the membrane can be replaced.

The Zilmet Ultra-Pro Vertical Expansion Vessel - 16 bar. - 100Ltr is a Pressure Vessel item.

The operating pressure of this is 16 bar.

Operation Overview

The ULTRA INOX PRO range of Expansion Vessels is specifically engineered for Unvented Potable Systems to deal with increased water volume resulting from heat expansion, solving issues of "water hammer" phenomenon, or reducing number of pump operations or duration of pump run. This product is manufactured by Zilmet. The Stainless Steel construction makes this vessel ideal for aggressive installation environments (E.g. coastal areas) and areas where environmental hygiene is of paramount concern. The interchangeable membrane gives unparalleled longevity.

Operation overview for Heat Expansion Purposes

The purpose of these vessels is to accommodate the increased liquid volume which occurs during system heating in an Unvented Circuit. A pressurised membrane enables ingress/egress of the liquid during periods of heating / cooling thus providing space for the expanded fluid volume to reside and prevent system pressure increase.
The sensible contraction of system water volume during cooling periods is enabled by means of a compressed air cushion which returns this temporarily expanded volume to the system.

The correct size of vessel must be considered prior to installation and installed by appropriately trained engineers. Careful consideration of pre charge must also be made as this is dependant on the application of the vessel. The larger size range available accommodates the larger systems and is also compatible with chilled water systems.

Operation overview for Water Hammer (Shock) Arrester Purposes

Also known as Hydraulic Shock, water hammer is a specific phenomenon and is not a "catch all" phrase for noisy pipes. The fitting of an ULTRA INOX PRO vessel will not resolve system noises where the root cause is excessive dynamic pressure, improperly clipped pipework or pipe bore restrictions due to clogged filters, burrs on cut pipe or excessive "bushing down" of distribution pipework.

Water hammer is caapplied when a water supply outlet is closed very suddenly. This causes a change in the momentum of the water when the system suddenly goes from a lower running pressure to a higher static pressure. This momentum impacts against the now closed outlet resulting in a potentially loud banging noise. This is commonly found in "quarter turn" type tap outlets and washing machines with solenoids controlling flow.

Siting an ULTRA INOX PRO as close to the source of the noise as possible will cause the vessels diaphragm to flex in response to this momentum change and prevent the audible impact against the terminal fittings. The pre charge should ideally be set to just slightly above the dynamic pressure of the system it is fitted to.

The Zilmet Ultra Inox-Pro Vertical Stainless Steel Expansion Vessel - 10 bar. - 100Ltr is a Pressure Vessel item.

The operating pressure of this is 10 bar.

The Zilmet Hydro-Pro Vertical Expansion Vessel - 10 bar. - 8Ltr - OBSOLETE is a Pressure Vessel item.

The operating pressure of this is 10 bar.

The Zilmet Inox-Pro Stainless Steel Expansion Vessel - 10 bar. - 8Ltr is a Pressure Vessel item.

The operating pressure of this is 10 bar.

The Zilmet Cal-Pro Vertical Expansion Vessel - 5 bar. - 8Ltr is a Pressure Vessel item.

The operating pressure of this is 5 bar.

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.

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 - Vertical - 100Ltr 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

The HeatWave Vessel - Inline - 8Ltr 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 - 100Ltr - Vertical is a Pressure Vessel item.

The operating pressure of this is 10 bar.

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

Purpose-built for EN 12828 heating and chilled-water systems, this multifunction sealed-system unit combines automatic expansion control, pressurisation, deaeration and make-up in a single package.

A pressure-step degassing process—using a controlled pressure drop and patented PALL-ring media—removes dissolved gases even at equilibrium. A replaceable butyl bladder stores the expansion fluid at atmospheric pressure. Supplied with Flexvent Super, height-adjustable feet and a weight-capacity sensor.

• All-in-one functionality — expansion, pressurisation, deaeration and make-up
• Pressure-step deaeration with PALL-ring technology
• Replaceable butyl bladder — easy maintenance and long service life
• Delivered complete — Flexvent Super, adjustable feet, weight-capacity sensor

Designed for commercial, industrial and residential sealed LPHW/CHW installations requiring efficient air removal and stable operating pressures.