Check Heat Transfer Fluid; Maintenance Of The Collector - Sonnenkraft SK500 Serie Manual

Betriebsempfehlungen
Operating tips
Consigli per la messa in funzione
Recommandations d'emploi
Recomendaciones para el funcionamiento
Flushing and filling
For safety reasons, charging is to be carried out only when there is no direct sunlight or when the collectors are
covered. Especially in areas liable to freezing, an anti-freeze/water mixture of up to 40 Vol.% must be used. To
protect materials from excessive thermal load, the system should be charged and commissioned as soon as
possible, after 4 weeks at the latest. Should this not be possible, it may be necessary to exchange the hydraulic
connectors prior to commissioning.
Attention:
Antifreeze that is not pre-mixed must be mixed with water prior to filling!Attention
Recommended antifreeze for flat plate collectors: FS
Hinweis: 40Vol.% proportion of antifreeze (60Vol.%/water) - freezing point: -22° C/solidification point: -26° C
50Vol.% proportion of antifreeze (50Vol.%/water) - freezing point: -32° C/solidification point: -44° C
It may not be possible to completely empty collectors once they have been filled. For this reason, collectors
exposed to frost should only be filled with a water/antifreeze mixture, also for pressure and function tests.
Alternatively, the pressure test can also be carried out using compressed air and leak detection spray.
Installing the temperature sensor
The temperature sensor should be installed in the sensor sleeve nearest to the collector array flow. To ensure
optimal contact between the sensor and the surrounding environment, the gap between the sensor sleeve and
the sensor element should be filled with a suitable conducting compound. All materials used for installing
temperature sensors (sensor element, conducting compound, cables, sealing and insulating materials) must be
suitably temperature resistant (up to 250° C).
Operating pressure
The maximum operating pressure is 10 bar.
Bleeding
The system must be bled:
- when commissioning the system (after filling the collectors)
- 4 weeks after commissioning
- when necessary, e.g. if there are malfunctions
WARNING:
Risk of scalding due to steam and hot heat transfer fluid
Only operate the bleeding valve if the temperature of the heat transfer fluid is < 60° C.
When bleeding the system, the collectors must not be hot! Cover the collectors and, if possible, bleed the system
in the morning.

Check heat transfer fluid

The heat transfer fluid must be checked every two years with regard to its antifreeze and pH value.
- Check antifreeze using antifreeze tester and replace or refill if necessary!
Target value is ca. - 25° C and - 30° C depending on climatic conditions.
- Check pH value with a pH indicator rod (target value approx. pH 7.5):
If the limit pH value is less than ≤ pH 7, replace the heat transfer fluid.

Maintenance of the collector

The collector or the collector array must be inspected visually, once a year, for any damage, leaks and
contamination. Condensate can form in the collector after commissioning and during times of the year with strong
outdoor temperature fluctuations. This condensate disappears however after a few hours exposure to sunlight.
Additional recommendations on operation and maintenance can be found in SONNENKRAFT'S general
documentation and instructions on commissioning and maintenance.
Decommissioning of the solar plant
If a solar plant is decommissioned for longer time it is recommended to cover the collectors to protect the solar
equipment in the circuit (e.g fluid, pump, expansion vessel etc.) against long time exposure to excess
temperature.
GB
SOLAR ENERGY MADE BRIGHTER
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