CDWT-215L – Fast Boiler & Buffer Tank in One Unit – 215 Litres (150L + 65L), Duplex 2205 Stainless Steel with Spiral Coil for Heat Pumps

The CDWT-215L Fast Boiler and Buffer Tank from Coolmark is a compact 2-in-1 solution designed for installations where energy efficiency, space-saving and high performance are essential. With 150 litres of domestic hot water storage and an additional 65 litres of buffer capacity for low-temperature heating, this unit is perfectly suited for heat pumps, solar energy systems, or hybrid heating configurations.

Both tanks are housed in one compact unit made of Duplex 2205 stainless steel – a premium-grade alloy known for its superior corrosion resistance, pressure stability and hygienic properties. Thanks to this robust material, the CDWT-215L is not only durable and low-maintenance, but also safe for potable water and suitable for use in humid or aggressive environments.

The integrated spiral coil heat exchanger, with a surface area of 1.7 m², provides rapid and efficient heat transfer, even at low supply temperatures. This makes it ideal for combination with air-to-water heat pumps or other low-temperature systems.

The tank is wrapped in 50 mm PUR rigid foam insulation, delivering excellent thermal performance and minimal standby losses. Its compact vertical design and versatile connection options make it a perfect fit for small technical rooms, cabinets, or renovation projects.

Key Benefits:

• Compact 2-in-1 design: 150L boiler + 65L buffer in one housing

• Duplex 2205 stainless steel: pressure- and corrosion-resistant, potable water safe

• 1.7 m² spiral heat exchanger: high transfer efficiency, heat pump-optimised

• 50 mm PUR insulation: excellent thermal retention, minimal energy loss

• Space-saving vertical unit: ideal for small rooms and tight spaces

• Easy installation: multiple ports and sensor inputs for control integration

• Low maintenance and energy-saving: suited for sustainable systems

Technical Specifications (Summary):

• Total volume: 215 litres

• Boiler tank: 150 litres

• Buffer tank: 65 litres

• Material: Duplex 2205 stainless steel

• Insulation: 50 mm PUR rigid foam

• Coil surface: 1.7 m²

• Heat exchanger output at 80/10/45 °C: approx. 18.7 kW

• Max. tank pressure: 10 bar

• Max. coil pressure: 16 bar

• Max. tank temperature: 95 °C

• Dimensions (H x Ø): 1280 x 650 mm

• Connections: G 1¼", G 1", sensor ports

Applications:

• Air-to-water and ground-source heat pumps

• Solar thermal and hybrid heating systems

• New builds, renovations, tiny homes, apartments

• Technical rooms with limited installation space

• Small commercial projects, vacation homes, agricultural use

The CDWT-215L is engineered for professionals and homeowners who need a compact, durable, and efficient hot water solution. With premium materials, smart design, and outstanding thermal performance, this unit is a valuable addition to any modern energy system.