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General Closed Loop System Schematics
Flushing and filling
For safety reasons you should only fill the collectors when there is no direct irradiation from the
sun (covering the collectors can be an option). Especially in regions exposed to frost, for flat plate
collectors you should use a mixture of anti freeze with water (40% anti freeze). The solar thermal
system should be filled and commissioned within one week of installation, because heat build-up
in the collector array can damage the flat gaskets in empty systems. If this is not possible, the flat
gaskets should be replaced before commissioning to prevent leakage.
Attention :
Anti freeze that is not premixed must be mixed with water prior to
charging the system.
Recommended antifreeze for flat plate collectors
– FHWM-GY-50005
25% antifreeze / 75% water mix - freeze point -10°C
40% antifreeze / 60% water mix - freeze point -22°C
50% antifreeze / 50% water mix - freeze point -32°C