Reflex - DD 12 Flow Through Expansion Vessel - 12 Ltr

The Refix DD 12 diaphragm expansion vessel is designed for flowed-through operation in domestic hot water systems, water supply installations and pressure-boosting systems. Built for cold water pipework applications, this vessel uses a high-flow circulation star and enclosed 3/4" T-piece to support effective flow-through performance, helping maintain water quality and reliable system operation.

Manufactured in accordance with DIN EN 13831 and checked to DIN 4807 Part 5, the Refix DD 12 features a butyl diaphragm designed in line with the elastomer directive and W 270. Internal and external coatings comply with KTW-A, while parts in contact with water are corrosion-protected to support long-term durability in demanding water system environments.

The vessel is suitable only for cold water systems and may also be combined with the Flowjet flow-through valve where required. Its compact design and flowed-through configuration make it a practical choice for potable water and booster applications where reliable pressure control and hygienic performance are important.

Key Product Features

• Refix DD 12 flowed-through diaphragm expansion vessel
• Suitable for DHW systems, water supply installations and pressure-boosting systems
• Only suitable for cold water systems
• Flow-through design with high-flow circulation star
• Supplied with enclosed 3/4" T-piece
• Designed and manufactured in accordance with DIN EN 13831
• Checked according to DIN 4807 Part 5
• Approved in line with Pressure Equipment Directive 2014/68/EU
• Vessels with 10/16 Bar permissible operating pressure and from 4 Litres with DIN DVGW registration no. NW-0411AT2534
• Non-replaceable butyl bladder according to DIN EN 13831, DIN 4807 T5, KTW-C and W270
• Interior and exterior coating in compliance with KTW-A
• Parts in contact with water are corrosion-protected
• May be combined with the Flowjet flow-through valve
• Type: DD 12
• Colour: Green
• Diaphragm material: Butyl
• Nominal volume: 12 Ltrs
• Maximum useful volume: 9 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: 280 mm
• Height: 318 mm
• Tilt dimension approx.: 424 mm
• Weight: 2.42 kg

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.