Product detailed description
How the Buderus Logasol solar thermal system works
A solar thermal system converts solar radiation falling on the roof into usable heat for heating domestic water and possibly also for space heating support. The heart of the system are the Logasol collectors placed on the roof or facade, which capture solar radiation and transfer it to the heat-carrying liquid (solar fluid) flowing in their absorber. This heated liquid travels through pipes down to the utility room, where in a storage water heater (Logalux) it transfers its heat via a heat exchanger to the domestic water or to the heating circuit. The cooled liquid then returns back to the collectors and the cycle repeats.
For this cycle to work reliably, accurately and safely all year round – in hot summer as well as freezing winter – the system needs several key components: a circulation pump that drives the liquid 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 components that protect the system against overpressure in case of overheating, and last but not least a quality frost-resistant solar fluid that will not freeze in winter and will withstand high temperatures at the collector in summer.
Why the pump station and connection set are important
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, contains check valves preventing unwanted circulation outside of operation (for example at night, when the storage tank could otherwise be cooled back down), a pressure gauge and flow meter for monitoring the circuit's condition, and a safety valve that safely releases overpressure if the maximum pressure is exceeded.
Connection and mounting sets, on the other hand, handle the mechanical and hydraulic interconnection of the collectors with each other and with the pipework leading into the house – that is, sealing, compensation for the thermal expansion of copper caused by large temperature differences (a 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 leaks, loss of expensive solar fluid, and in extreme cases even damage to the collector from overheating without a way to dissipate the 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 valve combined with a shut-off valve (which is usually closed after the system has been balanced, to prevent steam from escaping from the hot liquid) ensures that no air bubble remains in the circuit slowing down circulation.
Set SKN for an additional collector – expanding an existing row
This set is designed to expand the solar array with each additional Logasol SKN4.0 collector within the same row that was established with the "SKN for 1st collector" set. It includes the SKN4.0 collector itself and an expansion mounting kit, which mechanically and hydraulically connects the new collector to the neighboring collector in the row – without the need to duplicate the connection set to the house pipework or the venting set, since these components were already installed with the first collector in the row and serve the entire row together.
Thanks to this concept, the solar array can be gradually expanded exactly according to need – for example if domestic hot water consumption in the household increases, or if solar space heating support is added later – without having to buy a complete (and more expensive) base set again. When ordering, we recommend always starting with one "for 1st collector" set, followed by as many "for additional collector" sets as there are additional collectors to be added to that row.
What's included in the set
- Logasol SKN4.0 (8718530938) – 1 pc
- Expansion mounting kit for an additional collector (8718531018) – 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 interconnected with copper piping and connected to the pipework leading to the utility room. After insulating the pipework (it is important to use insulation resistant to high temperatures and UV radiation on exterior sections), a pressure test of the circuit is carried out using air or nitrogen, verifying the tightness of all joints before filling with the 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 utility room, and finally the solar controller is configured – the pump's switch-on and switch-off temperatures, the maximum storage tank temperature, and any collector overheating protection. Only after this complete commissioning and functional testing does the installation company hand over the system for use, together with a test and setting protocol.
Frequently asked questions
Do I need to buy solar fluid separately, or is it included in the set?
It 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 a quality solar fluid, when the system is operated correctly, is typically 5 to 7 years, after which replacement or at least a check of the concentration and pH by a service technician is recommended.
Is the installation suitable for a DIY approach?
Connecting the solar circuit, pressure testing, filling with fluid and setting up the controller should always be carried out by a qualified technician experienced with solar systems – this involves working under pressure with hot media at heights, where an installation error can cause leaks or damage to the roofing.
Can the system be expanded with more collectors later?
Yes, that is 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 gradually sized according to current domestic hot water needs, or expanded later if the need 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 the complete hydraulic connection, including the inlet and outlet to the pipework leading into the house, and the basic mounting bracket for the entire row. The set for each additional collector in the same row only includes the connecting and expansion parts needed to connect the neighboring collector, without duplicating components already installed – it is therefore cheaper and only addresses 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 the joints and the functioning of the pump is recommended, ideally during the regular annual service inspection of the heating system.
Warranty
Buderus brand products are covered by warranty according to the seller's general terms and conditions and the warranty conditions of the manufacturer Bosch Thermotechnik GmbH. You can find the exact warranty period and the conditions for its application in the enclosed warranty documentation for the product, or request it from our customer service before purchase.
