Product Overview & Application Area
The WK 400 heat pump storage tank is a compact combination tank for heating systems with a heat pump and hygienic domestic hot water preparation. The tank combines an upper hot water section with 330 l and a lower buffer section with 160 l to a calculated total volume of 490 l.
The WK series is designed for systems in which heating water is buffered and hot water is provided via a stainless steel corrugated pipe. This makes the WK 400 particularly suitable for system setups where heat pump, heating circuit, auxiliary heating, and domestic hot water preparation are to be combined in a space-saving manner.
Technology & Equipment
In the upper tank section, there is a stainless steel corrugated pipe heat exchanger with a heating surface of 9.5 m² and a maximum operating pressure of 10 bar. The lower buffer section is used for storing heating water and supports a quieter operation of the heating system.
The tank is designed for a maximum operating pressure of 5 bar and a maximum operating temperature of 95 °C. Two designated connections with 1 1/2" female thread are available for electric auxiliary heating. The connection areas for heating cartridges are structurally clearly designated and may only be used in accordance with the system planning.
Everyday Benefits
The WK 400 combines buffer function and hot water preparation in one tank, thereby reducing the space requirement compared to separate tank solutions. The hygienic hot water preparation via the stainless steel corrugated pipe supports demand-oriented drinking water heating in the flow-through principle.
With a reference value of 400 l discharge capacity at 40 °C, the tank provides clear technical orientation for hot water provision. The actual performance in operation depends on tank temperature, draw-off profile, auxiliary heating, hydraulic integration, and the control strategy of the overall system.
System Integration & Compatibility
The WK 400 heat pump storage tank is designed for integration into heating systems with a heat pump, heating circuits, sensors, controls, and optional electric backup heating. The charging and discharging connections in the upper and lower storage areas enable coordinated hydraulic integration into the respective system concept.
For control purposes, four sensor or controller connections with 1/2" female threads are available. This allows the relevant storage zones to be integrated into the system control. The design, connection sequence, and control strategy must match the specific hydraulics of the heating system.
Technical data at a glance
| Product family | Storage technology |
| Product type | Storage tank |
| Storage tank type | Heat pump storage tank |
| Storage volume | 490 l calculated total capacity |
| Hot water section | 330 l above |
| Buffer section | 160 l below |
| Heat exchanger | 1 stainless steel corrugated tube heat exchanger |
| Heating surface of stainless steel corrugated tube | 9.5 m² |
| Insulation | 100 mm EPS, 130 mm EPS or 150 mm EPS vacuum depending on version |
| Max. operating pressure tank | 5 bar |
| Max. operating pressure stainless steel corrugated pipe | 10 bar |
| Max. temperature | 95 °C |
| Height | 1640 mm with insulation |
| Width | 650 mm without insulation |
| Depth | 650 mm without insulation |
| Weight | 160 kg |
Installation
The storage tank must be placed on a load-bearing, level, and frost-free surface. Before installation, check the transport route, door widths, ceiling height, installation area, and the tilting dimension of 1540 mm. Depending on the installation situation, the insulation can only be fully mounted after the tank has been set up.
Hydraulic connections, drinking water connection, safety valves, venting, sensors, control, and electrical work must be carried out by qualified specialist personnel. Heating elements may only be operated at the designated connection sockets and only after proper electrical testing.
Notes
The storage tank is intended for heating water in the buffer area and for hot water preparation via the stainless steel corrugated pipe. Other media, impermissible operating pressures, impermissible temperatures, or improper electrical retrofits do not correspond to the intended use.
The discharge rate is a reference value under defined conditions. For the actual system performance, system temperatures, volume flows, auxiliary heating, heat pump, control, and hydraulic integration are decisive.
Scope of delivery
- Heat pump storage tank WK 400 in the selected insulation variant
- Connections according to the technical design of the storage tank
- Product data sheet
- Operating instructions