service department

freeze protection

freezing of heat exchangers

In the winter months your heat exchanger could freeze. This can cause the heat exchanger to fail.
To prevent this, there are some simple precautions that you can take.

To avoid freezing problems, Dorset recommends during the winter months to use ethylene glycol in the heat exchanger. To protect the system to – 25 °C, 40% ethylene glycol is required. Higher percentages need to be applied at lower temperatures. To determine these percentages, we advise you to consult the instructions for use of the ethylene glycol.

In order to use optimal heat in the summer months, it is important to switch back to water (unless you have a glycol-dimensioned system).

We hope to be of service to you with the above information. If you have any questions, please feel free to contact our service department: 0031 (0) 543-745402 or send an e-mail to

add 40% ethylene glycol to protect up to -25°C

switch back to 100% water during warmer period