x-buffer® combi

x-buffer combi – buffer storage and hot water storage.

The x-buffer combi combines buffer and hot water storage in one, providing cosy warmth for heating and plenty of hot water. All the electrical components are completely prewired and the innovative and flexible cable routing makes for short cable runs in tight spaces.

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Buffer and hot water storage

x-buffer combi

This contains all the crucial components for connecting an x-change heat pump and will impress you with its really straightforward and clear design.

The space-saving combined solution for heating (127 l buffer storage tank) and hot water (231 l domestic water storage tank) simplifies the entire process of installing the heat pump, and saves space and time during installation, thereby reducing the overall investment costs.

All maintenance is carried out from the front; even the 2 magnesium signal anodes featuring a visual indicator for anode replacement can be changed quickly and easily from there.


Compatible with:

x-change dynamic (ac) 8 AW E

x-change dynamic (ac) 8 AW I

x-change dynamic terra (pc) 7 / 12 BW I

x-change dynamic water (pc) 10 WW I

  • Buffer storage tank 127 litres

  • 231-litre domestic water storage tank (204 litres useable) with an internal 3.5 m² heat exchanger optimised for heat pumps

  • Integrated three-way switching valve for heating/domestic water with storage charging pump

  • Integrated screw-in radiators with an adjustable thermostat in both storage tanks

  • Circulation connection provided

  • Integrated circulation pump for unmixed heating circuit

  • Hydraulic and electric connections inside the system

  • Storage tank insulated and clad

  • Magnesium signal anode with visual indicator for anode replacement


heat storage

Not all of the energy generated by the heat pump always gets used immediately. In this case, it makes sense to store the heat generated from renewable energy sources efficiently and with the lowest possible losses. That makes heat storage an important component of any future-oriented heating system.

Whether we are talking about making rooms warm and cosy or providing hygienic domestic water: Heat storage is an important element of all modern heating systems.

Buffer storage systems

Buffer storage tanks keep heat generation and heat consumption completely separate. This means that heat is generated regardless of when it is consumed and your heat pump does not have to start up again every time you turn up a radiator, for example.

Hot water storage systems

Hot water storage tanks ensure that there is always enough hot water available, even if everyone wants a bath.

As with buffer storage tanks, generation and consumption are once again kept separate.

Combined storage tanks

Combined storage tanks incorporate buffer storage and hot water storage in one unit.

The two types of storage are kept strictly separate from one another. Combined storage is the optimal solution if you don’t have much space in the cellar but still want to have an efficient and environmentally friendly storage system.

Installation video

The special layering process ensures optimum stratification of water layers at different temperatures within the Kermi x-buffer layered buffer storage tank.

This process, which has a patent pending, all but eliminates turbulence so that virtually no mixing of cold and warm water can occur. The water flows into the storage tank slowly and can rise or sink, depending on the temperature. Together with the high-quality all-round insulation, this significantly minimises energy losses.

The innovative housing design of the x-buffer layered buffer storage tank makes it a great space-saving alternative.

The system takes up no more room than a conventional heating tank. Thanks to the special base design, the tilt dimension (when the tank is tilted diagonally) barely exceeds the installation height. As a result, the x-buffer layered buffer storage tank also differs from conventional storage models in terms of its external appearance and is absolutely ideal for low-ceilinged rooms in existing buildings. With the intelligent arrangement of the connections, the x-buffer also fits through narrow doors.


Fresh water station

The fresh water station for wall mounting is available in 4 different versions.

The electronically controlled hot water generation relies on the continuous flow principle, ensuring that hot water is heated as hygienically as possible and in line with demand.

The speed-controlled charge pump regulates the set tap temperature quickly and efficiently.

The Modbus interface for direct communication with the Kermi® x-center® control ensures maximum operating comfort via the heat pump control – optionally, up to 4 fresh water stations can be combined in a cascade

Fresh water station cascade set

A cascade set is needed for each additional fresh water station.

A maximum of four fresh water stations can be combined in total.

To install a fresh water cascade, you need a fresh water station with circulation to serve as the master; each additional slave station is then implemented without circulation.

Storage charging assembly

The storage charging assembly for wall mounting is available in different versions.

The integrated storage charging pump is speed-controlled (PWM) so that charging with the modulating x-change dynamic (pro) heat pump series can take place efficiently and in line with demand in every operating mode.

The components are pre-assembled on a platform and the insulation is already incorporated as well.

Heating circuit assembly

The “unmixed heating circuit” assembly consists of a circulation pump (delivery head of 6 m or 9 m) and the corresponding shut-off devices.

The “mixed heating circuit” assembly also has a mixer.

These components are pre-assembled on a platform and the insulation is already incorporated as well.

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