CDWT-300L – Fast Boiler & Buffer Tank in One Unit – 300 Litres (200L + 100L), Duplex 2205 Stainless Steel with Coil for Heat Pumps

The CDWT-300L Fast Boiler & Buffer Tank Combination from Coolmark is a compact 2-in-1 boiler solution, specially designed for modern heat pump systems. This unit combines a 200-litre boiler tank and a 100-litre buffer tank in one robust stainless steel housing – offering a space-saving and efficient all-in-one solution for domestic hot water and heating.

The tank is made of Duplex 2205 stainless steel, a premium material known for its exceptional corrosion resistance, strength, and hygienic properties. This makes it ideal for use in potable water systems and low-temperature heating in combination with heat pumps, solar boilers, or hybrid systems.

At the heart of the design is a high-performance spiral coil heat exchanger with a surface area of 2.1 m². It is optimised for low inlet temperatures typical of air-to-water heat pumps and ensures rapid, efficient thermal transfer to the domestic hot water supply.

The entire unit is wrapped in 50 mm PUR rigid foam insulation, offering excellent thermal retention and drastically reducing heat loss. With flexible connection options and a compact build, the CDWT-300L is ideal for both new installations and renovation projects.

Key Benefits:

• 2-in-1: 200L boiler + 100L buffer tank in one compact unit

• Duplex 2205 stainless steel: corrosion-resistant, pressure-resistant, hygienic

• Efficient spiral coil heat exchanger: 2.1 m² surface area, high transfer capacity

• Optimised for heat pumps: efficient at low temperatures

• 50 mm PUR insulation: minimal heat loss, high thermal efficiency

• Compact design: space-saving and installer-friendly

• Multiple connection options: easily integrated into any heating system

Technical Specifications (Summary):

• Total volume: 300 litres

• Boiler tank: 200 litres

• Buffer tank: 100 litres

• Tank material: Duplex 2205 stainless steel

• Insulation: 50 mm PUR rigid foam

• Coil surface area: 2.1 m²

• Heat exchanger output (80/10/45 °C): approx. 21.9 kW

• Max. tank pressure: 10 bar

• Max. coil pressure: 16 bar

• Max. tank temperature: 95 °C

• Dimensions (H x Ø): 1500 x 650 mm

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

Applications:

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

• Solar water heating and buffer combinations

• Hybrid heating systems

• Residential buildings, apartments, utility construction

• Renovations, technical rooms with limited space

The CDWT-300L is built for installers and professionals who prioritise quality, performance, and efficiency. With high-grade stainless steel, advanced coil technology, and premium insulation, this boiler-buffer combination is a sustainable solution with a minimal ecological footprint.