Reflex - Refix DE 33 ST Diaphragm Expansion Vessel - 33 Ltr

The Refix DE 33 ST diaphragm expansion vessel is designed for water supply installations that are not subject to DIN 1988 requirements, making it suitable for specialist systems such as fire extinguishing installations, service water systems, underfloor heating and heat source applications. Designed and manufactured in accordance with DIN EN 13831 and approved under Pressure Equipment Directive 2014/68/EC, this vessel is built for reliable pressure maintenance across demanding system environments.

The vessel features a butyl bladder in line with DIN EN 13831, with replaceable bladder construction from 50 Ltrs upwards. Parts in contact with water are corrosion-protected, while the durable epoxy resin coating supports long service life. It is also suitable for systems using antifreeze additives between 25% and 50%, making it a practical option for a wide range of closed-system applications.

The Refix DE 33 st is finished in blue and fitted with a standing design for stable installation. Pressure gauge and supply pressure valve protection is provided by a clip design on applicable variants, and the vessel is intended to deliver reliable and consistent performance in commercial and specialist water system installations.

Key Product Features

• Refix DE 33 st non-flowed through diaphragm expansion vessel
• Suitable for water supply installations not subject to DIN 1988
• Ideal for fire extinguishing systems, service water systems, underfloor heating and heat source installations
• Designed and manufactured in accordance with DIN EN 13831
• Approved in line with Pressure Equipment Directive 2014/68/EC
• Butyl bladder according to DIN EN 13831
• Replaceable bladder construction from 50 Ltrs upwards
• Suitable for antifreeze additive concentrations from 25% to 50%
• Parts in contact with water are corrosion-protected
• Durable epoxy resin coating
• Pressure gauge included on applicable types
• Pressure gauge and supply pressure valve protected by clip
• Type: DE 33 st
• Colour: Blue
• Diaphragm material: Butyl
• Nominal volume: 33 Ltrs
• Maximum useful volume: 23 Ltrs
• Minimum operating temperature: -10 °C
• Maximum system temperature: 70 °C
• Maximum operating pressure: 10 Bar
• Factory pre-charge pressure: 4 Bar
• Connection: G 3/4"
• Diameter: 354 mm
• Height: 520 mm
• High water connection: 66 mm
• Tilt dimension approx.: 529 mm
• Weight: 5.76 kg
• No licence requirement according to SWKI HE301-01 and SVTI for (PSV * VN ≤ 3,000 Bar * litre)

Reflex (est. 1898) is a German manufacturer of expansion vessels, pressurisation units and system components for heating and cooling networks. Their ranges support HVAC and potable water installations, commonly used in residential and commercial buildings for pressure maintenance, deaeration and system protection.