It protects solar panels against frost, corrosion and incrustations up to -28°C

TOPTHERM SOLAR 28 is a fluid specially formulated for the filling of flat or vacuum solar panels, containing propylene glycol (non-toxic), corrosion inhibitors and alkalinizing agents suitable for limiting corrosive phenomena under normal operating conditions and for neutralizing the acidity due to the phenomena of stagnation.
All the components are thermally stable at the temperature of 300° C and have a high alkaline reserve for a long permanence under normal operating conditions (over 5 years). The colour gradually disappears (discolouration) and indicates the inhibitor consumption and that the product must be replaced.
This method allows the product easy maintenance without using any equipment. Patent no. 1390461.

How to use

TOPTHERM SOLAR 28 must be added in solar systems without any dilution. It protects against frost up to -28° C. Verify periodically (every 2 -3 years) the pH of the solution circulating inside; if the level is lower than 7, the system must be drained and powerflushed.


TOPTHERM SOLAR 28 must be added in solar system panel without any dilution.

Environmental and safety information

TOPTHERM SOLAR 28 is formulated with propylene glycol (non-toxic) and it is not classified as hazardous substance. It is compatible (non-corrosive) with metals (iron-steel-copper) and plastic materials. Keep out of the reach of children. Do not mix with other chemicals. Do not allow the product to reach potable waters. Do not dispose of waste through the environment.


Il refrattometro viene utilizzato per il controllo della percentuale di antigelo presente nell’acqua e della temperatura di congelamento.


Filling operation
• Drain the solar plant.
• Check the quantity of fluid present inside the system or the system dimensions.
• If any sludge is inside, clean with the product TOPTHERM CLEAN SOL.
• Connect the external pump TOPFLUSH to the system.
• Ensure to have the right quantity of TOPTHERM SOLAR 28 available (lower concentration than the recommended do not yield satisfactory results. Any higher concentration do not cause problems).
• Check annually the antifreeze percentage and its pH. If the inhibitor originally colour has disappears and/or its pH level
• is lower than 8, replace it or add the antifreeze TOPTHERM SOLAR 28.