Product detailed description
Buderus is one of the oldest and most respected heating technology brands in Europe – its manufacturing tradition dates back to 1731. Today, Buderus is part of the Bosch Thermotechnik group, meaning that every product is backed by German engineering, strict quality control and decades of experience in developing heat sources, storage tanks and control technology. Thanks to this, customers can be confident they are investing in a solution designed for long-term, reliable operation.
Buderus Logalux SM400 solar combi storage tank, white
Buderus Set SM400, white is the larger sibling of the SM310 tank – a solar bivalent storage tank with a volume of 400 litres, designed for domestic hot water preparation combining solar collectors with a gas or other boiler. As with the SM310, it features a design with two heat exchangers: the lower, larger exchanger is connected to the solar circuit and ensures priority heating of water by solar energy, while the upper exchanger connected to the boiler reheats the water when solar gain is not sufficient to cover household demand.
The larger 400-litre volume allows more solar energy to be accumulated during the day and used even in the evening hours or during temporarily cloudy weather, increasing the share of solar coverage of the household's hot water needs. The white casing is durable and visually unobtrusive in technical rooms.
What's included in the set
The set includes the storage tank and a complete connection kit for the solar circuit:
- Logalux SM400 (code 8732929427, 1 pc)
- Sensor Set, RD 6.0 3000 10K (code 7735502288, 1 pc)
- THERMOSTATIC DHW MIXING VALVE (code 7735600273, 1 pc)
- Logafix expansion vessel MAG Solar, 25 l, 6 bar (code 7747202343, 1 pc)
- MB2 expansion vessel bracket (code 12222017, 1 pc)
The RD temperature sensor measures the water temperature for solar pump control, the thermostatic DHW mixing valve protects against scalding by blending in cold water when the tank temperature is high, and the Logafix expansion vessel (25 l, 6 bar) with the MB2 bracket serves as a safety element of the solar circuit, compensating for volume changes of the heat transfer fluid.
How to choose the right storage tank size
A 400-litre volume is suitable for larger households with 6 or more members, or for households that want to achieve a higher share of solar coverage of hot water needs and have a larger roof area available for solar collectors. As a general guideline, 1.2–1.5 m² of collector area is recommended per 100 litres of tank volume; however, exact sizing always depends on the location, roof orientation and expected consumption, and should be assessed by a designer or experienced installer.
Frequently Asked Questions
Why choose the SM400 instead of the SM310?
The SM400 with its 400-litre volume allows more solar energy to be accumulated and a higher share of solar coverage to be achieved, making it suitable for larger households or larger solar arrays.
Is a larger collector area needed for the SM400?
Yes, to make full use of the larger tank's potential, a proportionally larger area of solar collectors is recommended compared to the smaller SM310 model.
Does the set include a pump solar station?
No, the pump group (e.g. Logasol KS0110) is ordered separately; this set covers the storage tank and its connection/safety components.
What is the function of the thermostatic mixing valve?
It automatically blends cold water into the outlet if the temperature in the tank (for example during high solar gain) exceeds a safe limit, protecting the household from scalding.
Will a 400-litre tank fit into a standard boiler room?
This is a larger-volume tank with greater dimensions and weight; before purchase we recommend checking the dimensions and floor load capacity in the manufacturer's technical data sheet.
Can the tank be operated without solar collectors?
Yes, heating can be provided temporarily or permanently via the upper exchanger connected to the boiler only, and the solar circuit can be added later.
Installation and operation
Installation of the storage tank and its connection to the heating or solar circuit must be carried out exclusively by a qualified person with appropriate authorisation – this involves work on hot water, gas or electrical systems as well as pressure vessels, where incorrect installation could jeopardise operational safety and warranty validity. Before installation, we recommend checking that there is sufficient space at the installation site for service access (especially to the exchangers, anode and sensors), that the floor can bear the weight of the filled tank, and that drainage for any water from the safety valve is ensured.
After connection, the tank must be filled, vented and the control technology (sensors, or solar circuit control) set according to the project documentation and manufacturer's instructions. Regular servicing – checking the anode, tightness, pressure in the expansion vessel and function of the safety valve – extends the service life of the tank and reduces the risk of unexpected failure.
Warranty and service
Buderus products are generally covered by a 2-year statutory warranty. When the appliance is registered via the official Buderus portal and commissioned by an authorised service technician, an extended warranty on the tank's heat exchanger can typically be obtained under standard conditions – we recommend verifying the exact terms and length of the extended warranty directly during product registration or with an authorised Buderus service partner. The Buderus service network in Slovakia is extensive, spare parts are readily available, and if installation and maintenance instructions are followed, you can expect many years of trouble-free operation from the tank.
