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Testing PH level/Acidity on water boiler

Joseph_4 Member Posts: 278
Hi Do you test ph level before you install a forced water boiler? If you do what are the acceptable numbers. if numbers no good. How does one remedy the problem
Joseph Hardoon


  • GGross
    GGross Member Posts: 1,072
    Considering you have a history of failed heat exchanger it won't hurt to test PH. 7 is neutral and its what you are looking for. If the water is not super mucky, and the PH is close I would keep it with a dirt separator installed to get the little stuff over time. If the PH is off and the water is mucky I would flush the system thoroughly and start over with new demineralized water. Keep in mind the water that is in the system, so as long as it is "old" and is an acceptable PH, should have virtually nothing left in it to scale up the system, if there is junk or muck in the system you can filter that out with strainers and a dirt separator.

    Be extra cautious of your boiler water if adding ECM pumps, if you don't put in a magnetic separator and add in ECM pumps, the pump will become your new dirt separator.
  • hot_rod
    hot_rod Member Posts: 22,327
    It is also the mineral content you want to look at. A hardness test kit will indicate some of the scaling minerals. A TDS total dissolved solids is a better test as it shows all the minerals, positive and negative ions.

    Most boiler manuals will give you acceptable range for PH, TDS, sometimes chloride levels, especially important with stainless boilers.

    There is also an ASTM standard for boiler water quality.

    This is a good, quick read, about boiler water quality.


    A deeper dive here:
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Joseph_4
    Joseph_4 Member Posts: 278