




CDWT-300L – Fast Boiler Tank & Buffer Tank in one housing – 300 Liter (200L + 100L), Duplex 2205 Stainless Steel, with Spiral for Heat Pump
The Coolmark CDWT-300L Fast Boiler & Buffer Tank Combination is a compact 2-in-1 boiler solution, specially designed for the latest generation of heat pump systems. This unit combines a 200 litre boiler tank and a 100 litre buffer tank in one robust stainless steel housing, resulting in a space-saving and efficient total solution for hot water and heating.
The tank is made of Duplex 2205 stainless steel , a high-quality material known for its extreme corrosion resistance, strength and hygienic properties. This makes the boiler suitable for both drinking water installations and low-temperature heating in combination with heat pumps, solar boilers and hybrid systems.
At the heart of the design is a powerful 2.1 m² coil heat exchanger . Optimised for low flow temperatures such as those from air-to-water heat pumps, it ensures fast, efficient transfer of thermal energy to the domestic hot water.
The entire unit is equipped with 50 mm PUR rigid foam insulation all around with excellent insulation values, which significantly reduces heat loss and reduces energy consumption to a minimum. Thanks to the well-thought-out design and versatile connection options, this boiler is easy to integrate into both new installations and renovation projects.
Key benefits:
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2-in-1: 200L boiler tank + 100L buffer tank in one compact housing
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Duplex 2205 stainless steel: corrosion-resistant, pressure-resistant and suitable for drinking water systems
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Efficient spiral heat exchanger: 2.1 m² surface, high transfer capacity
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Optimized for heat pumps: maximum efficiency at low temperatures
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50 mm PUR insulation: excellent thermal protection, minimal heat loss
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Compact design: space-saving and easy to install
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Multiple connection options: flexible integration into any system
Technical specifications (summary):
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Total volume: 300 liters
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Boiler tank: 200 liters
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Buffer tank: 100 liters
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Tank material: Duplex 2205 stainless steel
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Insulation: 50 mm PUR hard foam
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Spiral surface: 2.1 m²
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Heat exchanger capacity at 80/10/45 °C: approx. 21.9 kW
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Max. working pressure tank: 10 bar
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Max. working pressure spiral: 16 bar
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Max. tank temperature: 95 °C
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Dimensions (h x Ø): 1500 x 650 mm
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Connections: G 1¼", G 1", temperature sensor inputs
Applications:
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Heat pump systems (air/water & ground/water)
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Solar boiler and buffer tank combinations
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Hybrid heating systems
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Residential construction, apartments, commercial construction
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Renovations, technical rooms with limited space
The CDWT-300L is designed for installers who do not want to compromise on quality, performance or efficiency. Thanks to the combination of high-quality stainless steel, an advanced spiral heat exchanger and smart insulation, this boiler-buffer tank combination offers a sustainable solution for modern installations with a minimal ecological footprint.