Product detailed description
How the Buderus Logasol solar thermal system works
A solar thermal system converts sunlight falling on the roof into usable heat for domestic hot water heating and possibly also for space heating support. The heart of the system are Logasol collectors mounted on the roof or facade, which capture solar radiation and transfer it to the heat transfer fluid (solar fluid) flowing through their absorber. This heated fluid travels through piping down to the plant room, where in a storage tank (Logalux) it transfers its heat via a heat exchanger to the domestic hot water or heating circuit. The cooled fluid then returns to the collectors and the cycle repeats.
For this cycle to work reliably, precisely, and safely all year round – in the hot summer and in the freezing winter – the system needs several key components: a circulation pump that drives the fluid in the circuit, a controller that evaluates the temperatures at the collector and in the storage tank and decides when the pump should run, safety and expansion elements that protect the system against overpressure during overheating, and last but not least, a quality frost-resistant solar fluid that won't freeze in winter and can withstand high temperatures at the collector in summer.
Why the pump station and connection set matter
The collector alone, without a properly sized pump station and connection accessories, cannot function safely or efficiently. The pump station ensures a controlled and measurable flow of solar fluid, includes check valves preventing unwanted circulation outside of operation (for example at night, when reverse cooling of the storage tank could occur), a pressure gauge and flow meter to monitor the circuit's condition, and a safety valve that safely relieves overpressure if the maximum pressure is exceeded.
Connection and mounting sets, on the other hand, handle the mechanical and hydraulic connection of the collectors to each other and to the piping leading into the house – that is, sealing, compensation for the thermal expansion of copper under large temperature differences (the collector can reach over 150 °C in summer, while dropping below freezing in winter), and secure anchoring to the roof or structure. Without a quality connection, there is a risk of leakage, loss of expensive solar fluid, and in extreme cases even damage to the collector from overheating without a way to dissipate heat.
The venting set also plays an irreplaceable role in the system – air trapped in the circuit significantly reduces heat transfer efficiency and causes noise and corrosion. An automatic air vent combined with a shut-off valve (which is usually closed after the system has been balanced, to prevent steam from escaping from the hot fluid) ensures that no air bubble remains in the circuit hindering circulation.
SKN Set for the 1st collector – the foundation for mounting a row of collectors
This set is designed as the initial, basic building block for installing a solar array with Logasol SKN4.0 collectors – flat-plate collectors with high efficiency suitable for both pitched and flat roofs. The set includes the SKN4.0 collector itself, a connection set that handles the hydraulic connection of the collector to the piping leading into the house (including the solar fluid inlet and outlet), an SKN4.0 venting set for removing air from the highest point of the circuit, and a basic mounting set designed for the entire first row of collectors – i.e., anchoring elements that secure the row to the roof structure or to a stand.
If you plan to install only one collector, this set contains everything needed for a complete hydraulic and mechanical connection. If you plan a row of several collectors side by side, this set forms the foundation of the row (the first collector with complete connection and mounting system), and for each additional collector in the same row you only need to purchase the separate, cheaper expansion set "SKN for additional collector," which only handles the connection and expansion of the mounting bracket without duplicating the connection and venting elements.
What's included in the set
- Logasol SKN4.0 (8718530938) – 1 pc
- SKN 4.0 connection set (8718531630) – 1 pc
- SKN4.0 venting set (8718531048) – 1 pc
- Basic mounting set for 1 row of collectors (8718531017) – 1 pc
Installation and commissioning
Installation of the solar circuit proceeds in several steps: first, the support structure and collectors are mechanically anchored to the roof or facade, then the collectors are connected to each other and to the piping leading to the plant room using copper piping. After insulating the piping (it is important to use insulation resistant to high temperatures and UV radiation on exterior sections), a pressure test of the circuit with air or nitrogen follows, verifying the tightness of all joints before filling with expensive solar fluid.
After a successful pressure test, the circuit is filled and vented with solar fluid using a filling and flushing pump, the pre-charge pressure in the expansion vessel is set according to the height difference between the collector and the plant room, and finally the solar controller is configured – the pump switching on/off temperatures, the maximum storage tank temperature, and any collector overheating protection. Only after this complete commissioning and functionality testing does the installation company hand over the system for use, along with a test and setting protocol.
Frequently Asked Questions
Do I need to buy solar fluid separately, or is it included in the set?
This depends on the specific package – see the "What's included in the set" list below. If the fluid is not included in a given set, we recommend the original frost-resistant Buderus Solar Fluid, which is developed specifically for the temperature and pressure stresses of Logasol solar circuits.
How often does the solar fluid need to be replaced?
The lifespan of quality solar fluid is typically 5 to 7 years when the system is operated correctly. After this time, replacement or at least a check of concentration and pH by a service technician is recommended.
Is the installation suitable for DIY?
Connecting the solar circuit, pressure testing, filling with fluid, and setting the controls should always be performed by a qualified technician experienced with solar systems – this involves working under pressure with hot media at heights, where installation errors can cause leaks or damage to the roof covering.
Can the system be expanded with additional collectors later?
Yes, that's exactly why Buderus offers separate sets for the first collector in a row and expansion sets for each additional collector – the system can thus be sized gradually according to current hot water demand or expanded later when demand increases.
What is the difference between the connection set for the 1st collector and for an additional collector?
The set for the first collector includes a complete hydraulic connection, including the inlet and outlet to the piping leading into the house, and a basic mounting bracket for the entire row. The set for each additional collector in the same row contains only the connecting and expansion parts needed to connect the neighboring collector, without duplicating already installed elements – it is therefore cheaper and only handles the expansion of an existing row.
Is regular maintenance required?
An annual check of the circuit pressure, the condition of the expansion vessel, the tightness of joints, and the functionality of the pump is recommended, ideally during a regular annual service inspection of the heating system.
Warranty
Buderus brand products are covered by a warranty in accordance with the seller's general terms and conditions and the warranty terms of the manufacturer, Bosch Thermotechnik GmbH. You can find the exact warranty period and conditions for making a claim in the enclosed warranty documentation for the product, or request them from our customer service before purchase.
