SUNSYSTEM SWP NL 400

SUNSYSTEM SWP NL 400 indirect domestic hot water tank for heat pumps

The SUNSYSTEM SWP NL 400 indirect domestic hot water tank is a DHW tank optimised for heat pump systems, featuring 1 coil heat exchanger with an extra-large heat transfer surface. Thanks to its larger, 374-litre capacity and enlarged heat exchanger surface, it is an ideal choice for systems that require fast production of large volumes of domestic hot water.

The tank is made with titanium-enamelled internal surface protection, which contributes to a long service life and hygienic water storage. The 50 mm thick rigid PU insulation helps retain heat, while the external PVC jacket provides durable, practical protection. The tank can be operated on mains systems with a pressure of up to 10 bar.

The built-in, extra-large-surface heat exchanger coil of the SUNSYSTEM SWP NL 400 can be connected to a heat pump, a condensing boiler or solar thermal collectors. The heat exchanger with a surface area of 3.9 m² and a capacity of 23.6 litres provides significantly greater heat transfer capacity than average-sized heat exchangers, enabling efficient and fast heating even with heat sources operating at lower flow temperatures, such as a heat pump.

During indirect heat transfer, the hot water circulating in the heat exchanger coil heats the mains water inside the tank. The heat exchanger, located in the lower part of the tank, helps heat the entire water volume evenly: the warming water rises, and cooler water from the upper part of the tank takes its place. This results in fast and efficient DHW production.

The tank also features a recirculation connection, so with a suitable system layout, hot water can be available more quickly at the taps. This increases comfort, as there is no need to run off the cooled water in the pipework before drawing hot water. The circulation pump required for the recirculation line is not included with the tank.

On request, the SWP NL 400 can be ordered for an additional charge with an electric heating element / thermostat set, as well as an accessory set consisting of an 8 bar safety valve, a thermometer and 3 height-adjustable feet. The electric heating element can be used as an alternative heat source, for example when the heat pump, boiler or other central heat generator is not in operation.

Key features

• Indirect domestic hot water tank for heat pump systems
• 374-litre steel tank body
• 1 coil heat exchanger with extra-large heat transfer surface
• Heat exchanger surface area: 3.9 m²
• Heat exchanger capacity: 23.6 litres
• Titanium enamel internal tank protection
• Cathode / anode type internal surface protection
• 50 mm thick rigid PU thermal insulation
• External PVC jacket
• Fitted with a recirculation connection
• Bottom / side inspection opening
• Drain connection
• 2 side measuring points for a thermometer or temperature sensor
• Internally threaded connections
• Maximum tank operating pressure: 10 bar
• Maximum tank operating temperature: 95 °C
• Maximum heat exchanger operating pressure: 16 bar
• Maximum heat exchanger operating temperature: 110 °C
• Factory quality control: 15 bar test pressure on the tank body, 25 bar test pressure on the heat exchanger
• Energy efficiency class: C
• Can be connected to a heat pump, condensing boiler and solar thermal collector

Heat transfer optimised for heat pump systems

One of the most important advantages of the SUNSYSTEM SWP NL 400 is its extra-large heat exchanger coil. In heat pump systems, domestic hot water often has to be produced efficiently at lower flow temperatures. The large, 3.9 m² heat transfer surface helps the tank deliver adequate performance even with a lower-temperature heat source.

The design of the heat exchanger coil enables fast heating, while its relatively lower operating temperature can help reduce limescale build-up on the heat exchanger surface.

Optional accessories

• Electric heating element / thermostat set
• Electric heating element with 3 / 4.5 / 6 kW output
• 8 bar overpressure safety valve
• Thermometer
• 3 height-adjustable feet

Standard equipment

• 374-litre steel tank body
• Heat exchanger coil with enlarged surface area
• Mains water connections
• Recirculation connection
• Bottom / side inspection opening
• Drain connection
• 2 side measuring points for a temperature sensor or thermometer
• 50 mm PU thermal insulation
• PVC external cladding
• 3-year manufacturer's warranty against tank corrosion perforation and water leakage

Useful information about capacity

For domestic hot water tanks with a heat exchanger, it is worth distinguishing between nominal, gross and net capacity. The nominal capacity is a rounded figure intended for guidance, which often also appears in the product name. The gross capacity refers to the actual internal tank volume, including the heat exchanger and its internal capacity. The net capacity, by contrast, indicates the usable domestic hot water volume.

Recommended use

The SUNSYSTEM SWP NL 400 indirect DHW tank is recommended for heat pump heating systems and systems combined with a condensing boiler or solar thermal collectors. Thanks to its larger capacity and extra-large heat exchanger surface, it is a particularly good choice for larger detached houses, properties with higher domestic hot water demand, or buildings where fast, efficient and reliable DHW production is important.