Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

pH Levels in a Radiant System

hot_rod Member Posts: 22,105
ph for the safety of all metals would be 7.5. Most tap water will fall low to mid 7's. Test it to know. Inexpensive pencil ph meters are a handy tool to own.

I'd say hardness of 8 grains or more should be handled before flling. High levels of calcium, silica and iron will coat heat exchanger surfaces and hurt performance. In the case of small tube HXers and aluminum boilers you REALLY need to watch water quality.

If you have stainless steel components boiler or indirect, chlorides need to be checked. most installation manuals will indicate acceptable levels for most of these numbers.

I feel a good hydronic conditioner chemical is worth it's weight in gold. Consider a cleaner first, then add a good conditioner for years of top performance and HX longevity.

hot rod
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream


  • Contractor_2
    Contractor_2 Member Posts: 4
    pH Levels in a Radiant System

    I was wondering if anyone new the safe pH level of the water you fill a radiant heating system with. Whats too high and whats too low?

    I know in many commercial jobs and in Europe radiant systems need to be filled with water that has run through a softener. Especially if the area has hard water.

    Any feedback would be appreciated. Thanks!
This discussion has been closed.