Most solar thermal systems use antifreeze as the liquid to transport heat from the solar panel to the cylinder. However, there are a few drain back systems that only use water. The antifreeze is normally non-toxic propylene glycol (as opposed to toxic ethylene glycol).

An antifreeze change may be required for your solar system. This is not always the case – we will test the condition of your system before we do.

Problems affecting the antifreeze condition

Although antifreeze is usually stable at high temperature, there are issues that affect the luquid’s condition. In particular, overheating reduces the serviceability of the fluid. If the antifreeze regularly overheats it can lead to:

  • a reduction in the life-span and efficiency of the antifreeze to protect the system.
  • degradation of the antifreeze, leading to acidity. This can potentially  lead to corrosion of the pipe work, solar cylinder or solar panel.
  • breakdown of the in-built inhibitors.
  • blockage of liquid channels in the system.

How often does antifreeze need changing?

Checking the condition of the antifreeze is part of our service procedure. If your system has been overheating on a regular basis, it may well be time for a change. If you suspect the antifreeze in your system may need to be changed, please contact us and we can discuss your requirements.