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Why Anti-Freeze Needs To Be Added To Floor Heating Boilers

If you have any experience with floor heating boilers, we are sure that you will be familiar with the addition of addition of anti-freeze to these systems. Do you know why this is done, what type of anti-freeze is used or how to do it? Do you understand the risks of the substance poisoning your home’s water supply? We have tried to answer as many of these questions in as much detail as possible in this article for your peace of mind.
Why is anti-freeze added to a boiler?
Essentially, anti-freeze is added to your floor heating system to reduce the risk of expensive damage in the pipes caused by freezing. It can also help to avoid costly water or even mold contamination, which occurs when these pipes burst or develop leaks.
  • Warning – Make sure you have purchased a good quality transfer pump, as cheap quality ones will not last long with handling anti-freeze.
  • Warning – Beware of water damage and loss of cover insurance issues, as some companies will not cover glycol based products.
What kind of anti-freeze is used?
Usually, non-toxic propylene glycol anti-freeze is used. It is essential that you have purchased the right product (one for heating, not for automobiles), as the chemicals are different and many others are toxic. It can be used in all components of your system, from the boiler and piping to radiators and pumps.
How might the anti-freeze leak into your water supply?
If your boiler includes a tankless coil that is used for making domestic hot water and if there is a simultaneous loss of water pressure inside the coil and a perforation or leak, anti-freeze may leak backwards into the water supply. Whilst this combination of events is unlikely, it is possible and it has happened.
Warning – some products are not suitable for use in heating systems that use galvanised steel piping, so check with the manufacturer.
How much anti-freeze is needed to protect against freezing?
It can be easy to tell when you have added enough anti-freeze to your boiler. A service tech will use a hydrometer designed to measure propylene glycol concentration – they will add the substance and circulate it through the system and check the concentration levels until it reaches the required temperature.
Do I need to drain the boiler beforehand?
The good news is that you won’t need to drain your floor heating boiler before adding anti-freeze – it is possible to add it to an existing system via a transfer pump. If you would like to clean the system before adding the substance, however, you will need to drain the boiler.
As you can see, the addition of anti-freeze to floor heating boilers is important for protecting your hydronic system against freezing and associated damage during the winter. Whilst it is possible to add the substance yourself, you should be wary of many of the DIY websites out there, as they are offering bad and potentially dangerous advice. Instead, we certainly recommend that you have a service tech complete the addition for you.

The following article is from one of our external contributors. It does not represent the opinion of Benzinga and has not been edited.


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