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.

analyizing water sample from hydronic system

what should the parameters on a residential hot water heating system ...water sample be? The system has pex,brass,copper and steel has materials. The boiler has stainless steel heat exchanger. Looking for ph,tds and perhaps other? Glycol %?


  • KCA_2
    KCA_2 Member Posts: 305
    I check certain levels

    when I do yearly maintenance...

     pH should be greater than 7 & below 9... 

    I'm not sure why your doing a TDS but you could tell the amount of oxidation or chemicals in the system by that...  You would need to check the house water as well to set a bench mark... 

    Glycol percentage (Propylene Glycol) is a matter of what you want as a freezing temp...  No more than 50% though and with glycol you would want to check the pH regularly...  As glycol works with oxygen it forms glycolic acid and that can be a problem for your metals...  Adding Di Potassium Phosphate will get the pH back up or you can dump it and add all new...

    If you have much oxidation you can add Sodium Molybdate to the system but please read up on it first ...  You only need to keep 2 ppm in the system.  There are a lot of additives out there but read the labels and don't put anything in the boiler without reading about it and understanding it...

    I hope I helped

     :-)  KCA
    :-) Ken
This discussion has been closed.